diff --git a/ngraph/frontend/onnx_import/include/onnx_import/core/tensor.hpp b/ngraph/frontend/onnx_import/include/onnx_import/core/tensor.hpp
index 0f0600477b3..94ae06e0563 100644
--- a/ngraph/frontend/onnx_import/include/onnx_import/core/tensor.hpp
+++ b/ngraph/frontend/onnx_import/include/onnx_import/core/tensor.hpp
@@ -23,6 +23,7 @@
 #include "ngraph/op/constant.hpp"
 #include "ngraph/shape.hpp"
 #include "ngraph/type/element_type.hpp"
+#include "tensor_external_data.hpp"
 
 namespace ngraph
 {
@@ -158,6 +159,30 @@ namespace ngraph
                             return std::vector<T>(
                                 it, it + (raw_data.size() / __get_onnx_data_size(onnx_data_type)));
                         }
+
+                        template <typename T>
+                        inline std::vector<T>
+                            get_external_data(const ONNX_NAMESPACE::TensorProto& tensor)
+                        {
+                            const auto tensor_external_data = TensorExternalData(tensor);
+                            const auto raw_data = tensor_external_data.load_external_data();
+
+                            return detail::__get_raw_data<T>(raw_data, tensor.data_type());
+                        }
+
+                        bool has_tensor_external_data(const ONNX_NAMESPACE::TensorProto& tensor)
+                        {
+                            if (tensor.has_data_location() &&
+                                tensor.data_location() == ONNX_NAMESPACE::TensorProto_DataLocation::
+                                                              TensorProto_DataLocation_EXTERNAL)
+                            {
+                                return true;
+                            }
+                            else
+                            {
+                                return false;
+                            }
+                        }
                     }
                 }
 
@@ -171,6 +196,10 @@ namespace ngraph
                 template <>
                 inline std::vector<double> get_data(const ONNX_NAMESPACE::TensorProto& tensor)
                 {
+                    if (detail::has_tensor_external_data(tensor))
+                    {
+                        return detail::get_external_data<double>(tensor);
+                    }
                     if (tensor.has_raw_data())
                     {
                         return detail::__get_raw_data<double>(tensor.raw_data(),
@@ -202,6 +231,10 @@ namespace ngraph
                 template <>
                 inline std::vector<float> get_data(const ONNX_NAMESPACE::TensorProto& tensor)
                 {
+                    if (detail::has_tensor_external_data(tensor))
+                    {
+                        return detail::get_external_data<float>(tensor);
+                    }
                     if (tensor.has_raw_data())
                     {
                         return detail::__get_raw_data<float>(tensor.raw_data(), tensor.data_type());
@@ -229,6 +262,10 @@ namespace ngraph
                 inline std::vector<ngraph::float16>
                     get_data(const ONNX_NAMESPACE::TensorProto& tensor)
                 {
+                    if (detail::has_tensor_external_data(tensor))
+                    {
+                        return detail::get_external_data<float16>(tensor);
+                    }
                     if (tensor.has_raw_data())
                     {
                         return detail::__get_raw_data<ngraph::float16>(tensor.raw_data(),
@@ -244,6 +281,10 @@ namespace ngraph
                 template <>
                 inline std::vector<int8_t> get_data(const ONNX_NAMESPACE::TensorProto& tensor)
                 {
+                    if (detail::has_tensor_external_data(tensor))
+                    {
+                        return detail::get_external_data<int8_t>(tensor);
+                    }
                     if (tensor.has_raw_data())
                     {
                         return detail::__get_raw_data<int8_t>(tensor.raw_data(),
@@ -259,6 +300,10 @@ namespace ngraph
                 template <>
                 inline std::vector<int16_t> get_data(const ONNX_NAMESPACE::TensorProto& tensor)
                 {
+                    if (detail::has_tensor_external_data(tensor))
+                    {
+                        return detail::get_external_data<int16_t>(tensor);
+                    }
                     if (tensor.has_raw_data())
                     {
                         return detail::__get_raw_data<int16_t>(tensor.raw_data(),
@@ -274,6 +319,10 @@ namespace ngraph
                 template <>
                 inline std::vector<int32_t> get_data(const ONNX_NAMESPACE::TensorProto& tensor)
                 {
+                    if (detail::has_tensor_external_data(tensor))
+                    {
+                        return detail::get_external_data<int32_t>(tensor);
+                    }
                     if (tensor.has_raw_data())
                     {
                         return detail::__get_raw_data<int32_t>(tensor.raw_data(),
@@ -289,6 +338,10 @@ namespace ngraph
                 template <>
                 inline std::vector<int64_t> get_data(const ONNX_NAMESPACE::TensorProto& tensor)
                 {
+                    if (detail::has_tensor_external_data(tensor))
+                    {
+                        return detail::get_external_data<int64_t>(tensor);
+                    }
                     if (tensor.has_raw_data())
                     {
                         return detail::__get_raw_data<int64_t>(tensor.raw_data(),
@@ -304,6 +357,10 @@ namespace ngraph
                 template <>
                 inline std::vector<uint8_t> get_data(const ONNX_NAMESPACE::TensorProto& tensor)
                 {
+                    if (detail::has_tensor_external_data(tensor))
+                    {
+                        return detail::get_external_data<uint8_t>(tensor);
+                    }
                     if (tensor.has_raw_data())
                     {
                         return detail::__get_raw_data<uint8_t>(tensor.raw_data(),
@@ -319,6 +376,10 @@ namespace ngraph
                 template <>
                 inline std::vector<uint16_t> get_data(const ONNX_NAMESPACE::TensorProto& tensor)
                 {
+                    if (detail::has_tensor_external_data(tensor))
+                    {
+                        return detail::get_external_data<uint16_t>(tensor);
+                    }
                     if (tensor.has_raw_data())
                     {
                         return detail::__get_raw_data<uint16_t>(tensor.raw_data(),
@@ -334,6 +395,10 @@ namespace ngraph
                 template <>
                 inline std::vector<uint32_t> get_data(const ONNX_NAMESPACE::TensorProto& tensor)
                 {
+                    if (detail::has_tensor_external_data(tensor))
+                    {
+                        return detail::get_external_data<uint32_t>(tensor);
+                    }
                     if (tensor.has_raw_data())
                     {
                         return detail::__get_raw_data<uint32_t>(tensor.raw_data(),
@@ -349,6 +414,10 @@ namespace ngraph
                 template <>
                 inline std::vector<uint64_t> get_data(const ONNX_NAMESPACE::TensorProto& tensor)
                 {
+                    if (detail::has_tensor_external_data(tensor))
+                    {
+                        return detail::get_external_data<uint64_t>(tensor);
+                    }
                     if (tensor.has_raw_data())
                     {
                         return detail::__get_raw_data<uint64_t>(tensor.raw_data(),
@@ -366,6 +435,10 @@ namespace ngraph
                 {
                     // Boolean values are stored as char because std::vector<bool>
                     // can behave differently from other vector containers.
+                    if (detail::has_tensor_external_data(tensor))
+                    {
+                        return detail::get_external_data<char>(tensor);
+                    }
                     if (tensor.has_raw_data())
                     {
                         return detail::__get_raw_data<char>(tensor.raw_data(), tensor.data_type());
diff --git a/ngraph/frontend/onnx_import/include/onnx_import/exceptions.hpp b/ngraph/frontend/onnx_import/include/onnx_import/exceptions.hpp
index f61a83469da..b74112e7f9d 100644
--- a/ngraph/frontend/onnx_import/include/onnx_import/exceptions.hpp
+++ b/ngraph/frontend/onnx_import/include/onnx_import/exceptions.hpp
@@ -21,6 +21,7 @@
 #include "ngraph/check.hpp"
 #include "ngraph/except.hpp"
 #include "onnx_import/core/node.hpp"
+#include "onnx_import/utils/tensor_external_data.hpp"
 
 namespace ngraph
 {
@@ -44,6 +45,15 @@ namespace ngraph
                 }
             };
 
+            struct invalid_external_data : ngraph_error
+            {
+                invalid_external_data(const onnx_import::detail::TensorExternalData& external_data)
+                    : ngraph_error{std::string{"invalid external data: "} +
+                                   external_data.to_string()}
+                {
+                }
+            };
+
         } // namespace  error
 
     } // namespace  onnx_import
diff --git a/ngraph/frontend/onnx_import/include/onnx_import/onnx.hpp b/ngraph/frontend/onnx_import/include/onnx_import/onnx.hpp
index 44d494da3bd..af3c8280415 100644
--- a/ngraph/frontend/onnx_import/include/onnx_import/onnx.hpp
+++ b/ngraph/frontend/onnx_import/include/onnx_import/onnx.hpp
@@ -62,11 +62,15 @@ namespace ngraph
         /// \note       If stream parsing fails or the ONNX model contains unsupported ops,
         ///             the function throws an ngraph_error exception.
         ///
-        /// \param[in]  stream    The input stream (e.g. file stream, memory stream, etc).
+        /// \param[in]  stream     The input stream (e.g. file stream, memory stream, etc).
+        /// \param[in]  model_path The path to the imported onnx model.
+        ///                        It is required if the imported model uses data saved in external
+        ///                        files.
         ///
         /// \return     An nGraph function that represents a single output from the created graph.
         ONNX_IMPORTER_API
-        std::shared_ptr<Function> import_onnx_model(std::istream& stream);
+        std::shared_ptr<Function> import_onnx_model(std::istream& stream,
+                                                    const std::string& model_path = "");
 
         /// \brief     Imports and converts an ONNX model from the input file
         ///            to an nGraph Function representation.
diff --git a/ngraph/frontend/onnx_import/include/onnx_import/utils/tensor_external_data.hpp b/ngraph/frontend/onnx_import/include/onnx_import/utils/tensor_external_data.hpp
new file mode 100644
index 00000000000..0baaef583cd
--- /dev/null
+++ b/ngraph/frontend/onnx_import/include/onnx_import/utils/tensor_external_data.hpp
@@ -0,0 +1,54 @@
+//*****************************************************************************
+// Copyright 2017-2019 Intel Corporation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//*****************************************************************************
+
+#pragma once
+
+#include <onnx/onnx_pb.h>
+
+namespace ngraph
+{
+    namespace onnx_import
+    {
+        namespace detail
+        {
+            /// \brief  Helper class used to load tensor data from external files
+            class TensorExternalData
+            {
+            public:
+                TensorExternalData(const ONNX_NAMESPACE::TensorProto& tensor);
+
+                /// \brief      Load external data from tensor passed to constructor
+                ///
+                /// \note       If read data from external file fails,
+                ///             the invalid_external_data is thrown
+                ///
+                /// \return     External binary data loaded into a std::string
+                std::string load_external_data() const;
+
+                /// \brief      Represets parameter of external data as string
+                ///
+                /// \return     State of TensorExternalData as string representation
+                std::string to_string() const;
+
+            private:
+                std::string m_data_location;
+                int m_offset = 0;
+                int m_data_lenght = 0;
+                int m_sha1_digest = 0;
+            };
+        }
+    }
+}
diff --git a/ngraph/frontend/onnx_import/src/core/graph.cpp b/ngraph/frontend/onnx_import/src/core/graph.cpp
index 4897d52f2d5..0287bbb0fc8 100644
--- a/ngraph/frontend/onnx_import/src/core/graph.cpp
+++ b/ngraph/frontend/onnx_import/src/core/graph.cpp
@@ -88,6 +88,11 @@ namespace ngraph
                     {
                         ng_constant = tensor.get_ng_constant();
                     }
+                    catch (const error::invalid_external_data&)
+                    {
+                        // invalid external data makes initializers creation impossible
+                        throw;
+                    }
                     catch (const ngraph::ngraph_error& exc)
                     {
                         NGRAPH_WARN << "Could not create an nGraph Constant for initializer '"
diff --git a/ngraph/frontend/onnx_import/src/onnx.cpp b/ngraph/frontend/onnx_import/src/onnx.cpp
index c398e49a729..b3e8b7e99b6 100644
--- a/ngraph/frontend/onnx_import/src/onnx.cpp
+++ b/ngraph/frontend/onnx_import/src/onnx.cpp
@@ -20,6 +20,7 @@
 #include <memory>
 
 #include "ngraph/except.hpp"
+#include "ngraph/file_util.hpp"
 #include "onnx_import/core/graph.hpp"
 #include "onnx_import/core/model.hpp"
 #include "onnx_import/onnx.hpp"
@@ -96,6 +97,38 @@ namespace ngraph
                 }
             }
 
+            // The paths to external data files are stored as relative to model path.
+            // The helper function below combines them and replaces the original relative path.
+            // As a result in futher processing data from external files can be read directly.
+            void update_external_data_paths(ONNX_NAMESPACE::ModelProto& model_proto,
+                                            const std::string& model_path)
+            {
+                if (model_path.empty())
+                {
+                    return;
+                }
+                const auto model_dir_path = file_util::get_directory(model_path);
+                auto graph_proto = model_proto.mutable_graph();
+                for (auto& initializer_tensor : *graph_proto->mutable_initializer())
+                {
+                    const auto location_key_value_index = 0;
+                    if (initializer_tensor.has_data_location() &&
+                        initializer_tensor.data_location() ==
+                            ONNX_NAMESPACE::TensorProto_DataLocation::
+                                TensorProto_DataLocation_EXTERNAL)
+                    {
+                        const auto external_data_relative_path =
+                            initializer_tensor.external_data(location_key_value_index).value();
+                        const auto external_data_full_path =
+                            file_util::path_join(model_dir_path, external_data_relative_path);
+
+                        // Set full paths to the external file
+                        initializer_tensor.mutable_external_data(location_key_value_index)
+                            ->set_value(external_data_full_path);
+                    }
+                }
+            }
+
             std::shared_ptr<Function>
                 convert_to_ng_function(const ONNX_NAMESPACE::ModelProto& model_proto)
             {
@@ -112,7 +145,8 @@ namespace ngraph
             }
         } // namespace detail
 
-        std::shared_ptr<Function> import_onnx_model(std::istream& stream)
+        std::shared_ptr<Function> import_onnx_model(std::istream& stream,
+                                                    const std::string& model_path)
         {
             if (!stream.good())
             {
@@ -144,6 +178,7 @@ namespace ngraph
             }
 
             detail::fixup_legacy_operators(model_proto.mutable_graph());
+            detail::update_external_data_paths(model_proto, model_path);
 
             return detail::convert_to_ng_function(model_proto);
         }
@@ -155,7 +190,7 @@ namespace ngraph
             {
                 throw detail::error::file_open{file_path};
             }
-            return import_onnx_model(ifs);
+            return import_onnx_model(ifs, file_path);
         }
 
         std::set<std::string> get_supported_operators(std::int64_t version,
diff --git a/ngraph/frontend/onnx_import/src/utils/tensor_external_data.cpp b/ngraph/frontend/onnx_import/src/utils/tensor_external_data.cpp
new file mode 100644
index 00000000000..c7cfd5e3d83
--- /dev/null
+++ b/ngraph/frontend/onnx_import/src/utils/tensor_external_data.cpp
@@ -0,0 +1,93 @@
+//*****************************************************************************
+// Copyright 2017-2019 Intel Corporation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//*****************************************************************************
+
+#include <fstream>
+#include <sstream>
+
+#include "ngraph/log.hpp"
+#include "onnx_import/exceptions.hpp"
+#include "tensor_external_data.hpp"
+
+namespace ngraph
+{
+    namespace onnx_import
+    {
+        namespace detail
+        {
+            TensorExternalData::TensorExternalData(const ONNX_NAMESPACE::TensorProto& tensor)
+            {
+                for (const auto& entry : tensor.external_data())
+                {
+                    if (entry.key() == "location")
+                        m_data_location = entry.value();
+                    if (entry.key() == "offset")
+                        m_offset = std::stoi(entry.value());
+                    if (entry.key() == "length")
+                        m_data_lenght = std::stoi(entry.value());
+                    if (entry.key() == "checksum")
+                        m_sha1_digest = std::stoi(entry.value());
+                }
+            }
+
+            std::string TensorExternalData::load_external_data() const
+            {
+                std::ifstream external_data_stream(m_data_location,
+                                                   std::ios::binary | std::ios::in | std::ios::ate);
+                if (external_data_stream.fail())
+                    throw error::invalid_external_data{*this};
+
+                std::streamsize read_data_lenght;
+                if (m_data_lenght == 0) // read entire file
+                    read_data_lenght = external_data_stream.tellg();
+                else
+                    read_data_lenght = m_data_lenght;
+
+                const auto page_size = 4096;
+                if (m_offset != 0 && m_offset % page_size != 0)
+                {
+                    NGRAPH_WARN << "offset should be multiples 4096 (page size) to enable mmap "
+                                   "support, current value is "
+                                << m_offset;
+                }
+                // default value of m_offset is 0
+                external_data_stream.seekg(m_offset, std::ios::beg);
+
+                if (m_sha1_digest != 0)
+                {
+                    NGRAPH_WARN << "SHA1 checksum is not supported";
+                }
+
+                std::string read_data;
+                read_data.resize(read_data_lenght);
+                external_data_stream.read(&read_data[0], read_data_lenght);
+                external_data_stream.close();
+
+                return read_data;
+            }
+
+            std::string TensorExternalData::to_string() const
+            {
+                std::stringstream s;
+                s << "ExternalDataInfo(";
+                s << "data_full_path: " << m_data_location;
+                s << ", offset: " << m_offset;
+                s << ", data_lenght: " << m_data_lenght;
+                s << ", sha1_digest: " << m_sha1_digest << ")";
+                return s.str();
+            }
+        }
+    }
+}
diff --git a/ngraph/test/CMakeLists.txt b/ngraph/test/CMakeLists.txt
index 31224ab75a3..8052d0de4df 100644
--- a/ngraph/test/CMakeLists.txt
+++ b/ngraph/test/CMakeLists.txt
@@ -353,6 +353,7 @@ if (NGRAPH_ONNX_IMPORT_ENABLE AND NOT NGRAPH_USE_PROTOBUF_LITE)
             onnx/onnx_import_const_folding.in.cpp
             onnx/onnx_import_convpool.in.cpp
             onnx/onnx_import_dyn_shapes.in.cpp
+            onnx/onnx_import_external_data.in.cpp
             onnx/onnx_import_library.in.cpp
             onnx/onnx_import_provenance.in.cpp
             onnx/onnx_import_reshape.in.cpp
diff --git a/ngraph/test/files/onnx/external_data/a/tensor_a.data b/ngraph/test/files/onnx/external_data/a/tensor_a.data
new file mode 100644
index 00000000000..489b4be7407
Binary files /dev/null and b/ngraph/test/files/onnx/external_data/a/tensor_a.data differ
diff --git a/ngraph/test/files/onnx/external_data/b/tensor_b.data b/ngraph/test/files/onnx/external_data/b/tensor_b.data
new file mode 100644
index 00000000000..672b9cba6f0
Binary files /dev/null and b/ngraph/test/files/onnx/external_data/b/tensor_b.data differ
diff --git a/ngraph/test/files/onnx/external_data/multiple_tensors.data b/ngraph/test/files/onnx/external_data/multiple_tensors.data
new file mode 100644
index 00000000000..eebacc956fa
Binary files /dev/null and b/ngraph/test/files/onnx/external_data/multiple_tensors.data differ
diff --git a/ngraph/test/files/onnx/external_data/tensor.data b/ngraph/test/files/onnx/external_data/tensor.data
new file mode 100644
index 00000000000..8db91db9674
Binary files /dev/null and b/ngraph/test/files/onnx/external_data/tensor.data differ
diff --git a/ngraph/test/files/onnx/external_data/tensor_optional_fields.data b/ngraph/test/files/onnx/external_data/tensor_optional_fields.data
new file mode 100644
index 00000000000..d7f6b6967e0
Binary files /dev/null and b/ngraph/test/files/onnx/external_data/tensor_optional_fields.data differ
diff --git a/ngraph/test/models/onnx/external_data.prototxt b/ngraph/test/models/onnx/external_data.prototxt
new file mode 100644
index 00000000000..62465aa0fe5
--- /dev/null
+++ b/ngraph/test/models/onnx/external_data.prototxt
@@ -0,0 +1,99 @@
+ir_version: 3
+producer_name: "nGraph ONNX Importer"
+graph {
+  node {
+    output: "B"
+    op_type: "Constant"
+    attribute {
+      name: "value"
+      t {
+        dims: 2
+        dims: 2
+        data_type: 1
+        float_data: 1
+        float_data: 2
+        float_data: 3
+        float_data: 4
+        name: "const_tensor"
+      }
+      type: TENSOR
+    }
+  }
+  node {
+    input: "A"
+    input: "B"
+    output: "X"
+    name: "add_node1"
+    op_type: "Add"
+  }
+  node {
+    input: "X"
+    input: "C"
+    output: "Y"
+    name: "add_node2"
+    op_type: "Add"
+  }
+  name: "test_graph"
+  initializer {
+    dims: 2
+    dims: 2
+    data_type: 1
+    name: "A"
+    external_data {
+        key: "location",
+        value: "../../files/onnx/external_data/tensor.data"
+    }
+    data_location: 1
+  }
+  input {
+    name: "A"
+    type {
+      tensor_type {
+        elem_type: 1
+        shape {
+          dim {
+            dim_value: 2
+          }
+          dim {
+            dim_value: 2
+          }
+        }
+      }
+    }
+  }
+  input {
+    name: "C"
+    type {
+      tensor_type {
+        elem_type: 1
+        shape {
+          dim {
+            dim_value: 2
+          }
+          dim {
+            dim_value: 2
+          }
+        }
+      }
+    }
+  }
+  output {
+    name: "Y"
+    type {
+      tensor_type {
+        elem_type: 1
+        shape {
+          dim {
+            dim_value: 2
+          }
+          dim {
+            dim_value: 2
+          }
+        }
+      }
+    }
+  }
+}
+opset_import {
+  version: 4
+}
diff --git a/ngraph/test/models/onnx/external_data_different_paths.prototxt b/ngraph/test/models/onnx/external_data_different_paths.prototxt
new file mode 100644
index 00000000000..22133570f3a
--- /dev/null
+++ b/ngraph/test/models/onnx/external_data_different_paths.prototxt
@@ -0,0 +1,87 @@
+ir_version: 3
+producer_name: "nGraph ONNX Importer"
+graph {
+  node {
+    input: "data_a"
+    input: "data_b"
+    input: "data_c"
+    output: "result"
+    op_type: "Mean"
+  }
+  name: "test_mean_example"
+  initializer {
+    dims: 1
+    data_type: 1
+    name: "data_a"
+    external_data {
+        key: "location",
+        value: "../../files/onnx/external_data/a/tensor_a.data"
+    }
+    data_location: 1
+  }
+  initializer {
+    dims: 3
+    data_type: 1
+    name: "data_b"
+    external_data {
+        key: "location",
+        value: "../../files/onnx/external_data/b/tensor_b.data"
+    }
+    data_location: 1
+  }
+  input {
+    name: "data_a"
+    type {
+      tensor_type {
+        elem_type: 1
+        shape {
+          dim {
+            dim_value: 1
+          }
+        }
+      }
+    }
+  }
+  input {
+    name: "data_b"
+    type {
+      tensor_type {
+        elem_type: 1
+        shape {
+          dim {
+            dim_value: 3
+          }
+        }
+      }
+    }
+  }
+  input {
+    name: "data_c"
+    type {
+      tensor_type {
+        elem_type: 1
+        shape {
+          dim {
+            dim_value: 3
+          }
+        }
+      }
+    }
+  }
+  output {
+    name: "result"
+    type {
+      tensor_type {
+        elem_type: 1
+        shape {
+          dim {
+            dim_value: 3
+          }
+        }
+      }
+    }
+  }
+}
+opset_import {
+  version: 8
+}
diff --git a/ngraph/test/models/onnx/external_data_file_not_found.prototxt b/ngraph/test/models/onnx/external_data_file_not_found.prototxt
new file mode 100644
index 00000000000..f65b8186aa8
--- /dev/null
+++ b/ngraph/test/models/onnx/external_data_file_not_found.prototxt
@@ -0,0 +1,82 @@
+ir_version: 3
+producer_name: "nGraph ONNX Importer"
+graph {
+  node {
+    input: "A"
+    input: "B"
+    output: "Y"
+    name: "add"
+    op_type: "Add"
+  }
+  name: "test_graph"
+  initializer {
+    dims: 2
+    dims: 2
+    data_type: 1
+    name: "A"
+    external_data {
+        key: "location",
+        value: "not_existed_file.data"
+    }
+    external_data {
+        key: "offset",
+        value: "4096"
+    }
+    external_data {
+        key: "length",
+        value: "16"
+    }
+    data_location: 1
+  }
+  input {
+    name: "A"
+    type {
+      tensor_type {
+        elem_type: 1
+        shape {
+          dim {
+            dim_value: 2
+          }
+          dim {
+            dim_value: 2
+          }
+        }
+      }
+    }
+  }
+  input {
+    name: "B"
+    type {
+      tensor_type {
+        elem_type: 1
+        shape {
+          dim {
+            dim_value: 2
+          }
+          dim {
+            dim_value: 2
+          }
+        }
+      }
+    }
+  }
+  output {
+    name: "Y"
+    type {
+      tensor_type {
+        elem_type: 1
+        shape {
+          dim {
+            dim_value: 2
+          }
+          dim {
+            dim_value: 2
+          }
+        }
+      }
+    }
+  }
+}
+opset_import {
+  version: 4
+}
diff --git a/ngraph/test/models/onnx/external_data_optional_fields.prototxt b/ngraph/test/models/onnx/external_data_optional_fields.prototxt
new file mode 100644
index 00000000000..8438d377b41
--- /dev/null
+++ b/ngraph/test/models/onnx/external_data_optional_fields.prototxt
@@ -0,0 +1,107 @@
+ir_version: 3
+producer_name: "nGraph ONNX Importer"
+graph {
+  node {
+    output: "B"
+    op_type: "Constant"
+    attribute {
+      name: "value"
+      t {
+        dims: 2
+        dims: 2
+        data_type: 1
+        float_data: 1
+        float_data: 2
+        float_data: 3
+        float_data: 4
+        name: "const_tensor"
+      }
+      type: TENSOR
+    }
+  }
+  node {
+    input: "A"
+    input: "B"
+    output: "X"
+    name: "add_node1"
+    op_type: "Add"
+  }
+  node {
+    input: "X"
+    input: "C"
+    output: "Y"
+    name: "add_node2"
+    op_type: "Add"
+  }
+  name: "test_graph"
+  initializer {
+    dims: 2
+    dims: 2
+    data_type: 1
+    name: "A"
+    external_data {
+        key: "location",
+        value: "../../files/onnx/external_data/tensor_optional_fields.data"
+    }
+    external_data {
+        key: "offset",
+        value: "4096"
+    }
+    external_data {
+        key: "length",
+        value: "16"
+    }
+    data_location: 1
+  }
+  input {
+    name: "A"
+    type {
+      tensor_type {
+        elem_type: 1
+        shape {
+          dim {
+            dim_value: 2
+          }
+          dim {
+            dim_value: 2
+          }
+        }
+      }
+    }
+  }
+  input {
+    name: "C"
+    type {
+      tensor_type {
+        elem_type: 1
+        shape {
+          dim {
+            dim_value: 2
+          }
+          dim {
+            dim_value: 2
+          }
+        }
+      }
+    }
+  }
+  output {
+    name: "Y"
+    type {
+      tensor_type {
+        elem_type: 1
+        shape {
+          dim {
+            dim_value: 2
+          }
+          dim {
+            dim_value: 2
+          }
+        }
+      }
+    }
+  }
+}
+opset_import {
+  version: 4
+}
diff --git a/ngraph/test/models/onnx/external_data_two_tensors_data_in_the_same_file.prototxt b/ngraph/test/models/onnx/external_data_two_tensors_data_in_the_same_file.prototxt
new file mode 100644
index 00000000000..3f24f37749b
--- /dev/null
+++ b/ngraph/test/models/onnx/external_data_two_tensors_data_in_the_same_file.prototxt
@@ -0,0 +1,103 @@
+ir_version: 3
+producer_name: "nGraph ONNX Importer"
+graph {
+  node {
+    input: "data_a"
+    input: "data_b"
+    input: "data_c"
+    output: "result"
+    op_type: "Max"
+  }
+  name: "test_mean_example"
+  initializer {
+    dims: 3
+    data_type: 6
+    name: "data_a"
+    external_data {
+        key: "location",
+        value: "../../files/onnx/external_data/multiple_tensors.data"
+    }
+    external_data {
+        key: "offset",
+        value: "0"
+    }
+    external_data {
+        key: "length",
+        value: "12"
+    }
+    data_location: 1
+  }
+  initializer {
+    dims: 3
+    data_type: 6
+    name: "data_b"
+    external_data {
+        key: "location",
+        value: "../../files/onnx/external_data/multiple_tensors.data"
+    }
+    external_data {
+        key: "offset",
+        value: "4096"
+    }
+    external_data {
+        key: "length",
+        value: "12"
+    }
+    data_location: 1
+  }
+  input {
+    name: "data_a"
+    type {
+      tensor_type {
+        elem_type: 6
+        shape {
+          dim {
+            dim_value: 3
+          }
+        }
+      }
+    }
+  }
+  input {
+    name: "data_b"
+    type {
+      tensor_type {
+        elem_type: 6
+        shape {
+          dim {
+            dim_value: 3
+          }
+        }
+      }
+    }
+  }
+  input {
+    name: "data_c"
+    type {
+      tensor_type {
+        elem_type: 6
+        shape {
+          dim {
+            dim_value: 3
+          }
+        }
+      }
+    }
+  }
+  output {
+    name: "result"
+    type {
+      tensor_type {
+        elem_type: 6
+        shape {
+          dim {
+            dim_value: 3
+          }
+        }
+      }
+    }
+  }
+}
+opset_import {
+  version: 8
+}
diff --git a/ngraph/test/onnx/onnx_import_external_data.in.cpp b/ngraph/test/onnx/onnx_import_external_data.in.cpp
new file mode 100644
index 00000000000..e9217bcc20b
--- /dev/null
+++ b/ngraph/test/onnx/onnx_import_external_data.in.cpp
@@ -0,0 +1,121 @@
+//*****************************************************************************
+// Copyright 2017-2020 Intel Corporation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//*****************************************************************************
+
+#include "gtest/gtest.h"
+#include "ngraph/file_util.hpp"
+#include "ngraph/type/element_type.hpp"
+#include "onnx_import/default_opset.hpp"
+#include "onnx_import/onnx.hpp"
+#include "util/engine/test_engines.hpp"
+#include "util/test_case.hpp"
+#include "util/test_control.hpp"
+#include "util/test_tools.hpp"
+#include "util/type_prop.hpp"
+
+using namespace ngraph;
+using namespace ngraph::onnx_import;
+using namespace ngraph::test;
+
+static std::string s_manifest = "${MANIFEST}";
+
+using TestEngine = test::ENGINE_CLASS_NAME(${BACKEND_NAME});
+
+NGRAPH_TEST(${BACKEND_NAME}, onnx_external_data)
+{
+    const auto function = onnx_import::import_onnx_model(
+        file_util::path_join(SERIALIZED_ZOO, "onnx/external_data.prototxt"));
+
+    auto test_case = test::TestCase<TestEngine>(function);
+    test_case.add_input<float>({1.f, 2.f, 3.f, 4.f});
+    test_case.add_expected_output<float>(Shape{2, 2}, {3.f, 6.f, 9.f, 12.f});
+
+    test_case.run();
+}
+
+NGRAPH_TEST(${BACKEND_NAME}, onnx_external_data_from_stream)
+{
+    std::string path = file_util::path_join(SERIALIZED_ZOO, "onnx/external_data.prototxt");
+    std::ifstream stream{path, std::ios::in | std::ios::binary};
+    ASSERT_TRUE(stream.is_open());
+    const auto function = onnx_import::import_onnx_model(stream, path);
+
+    auto test_case = test::TestCase<TestEngine>(function);
+    test_case.add_input<float>({1.f, 2.f, 3.f, 4.f});
+    test_case.add_expected_output<float>(Shape{2, 2}, {3.f, 6.f, 9.f, 12.f});
+
+    test_case.run();
+
+    stream.close();
+}
+
+NGRAPH_TEST(${BACKEND_NAME}, onnx_external_data_optinal_fields)
+{
+    const auto function = onnx_import::import_onnx_model(
+        file_util::path_join(SERIALIZED_ZOO, "onnx/external_data_optional_fields.prototxt"));
+
+    auto test_case = test::TestCase<TestEngine>(function);
+    test_case.add_input<float>({1.f, 2.f, 3.f, 4.f});
+    test_case.add_expected_output<float>(Shape{2, 2}, {3.f, 6.f, 9.f, 12.f});
+
+    test_case.run();
+}
+
+NGRAPH_TEST(${BACKEND_NAME}, onnx_external_data_in_different_paths)
+{
+    auto function = onnx_import::import_onnx_model(
+        file_util::path_join(SERIALIZED_ZOO, "onnx/external_data_different_paths.prototxt"));
+
+    auto test_case = test::TestCase<TestEngine>(function);
+    // first input: {3.f}, second: {1.f, 2.f, 5.f} read from external files
+    test_case.add_input<float>({2.f, 7.f, 7.f});
+
+    test_case.add_expected_output<float>({2.f, 4.f, 5.f});
+    test_case.run();
+}
+
+NGRAPH_TEST(${BACKEND_NAME}, onnx_external_two_tensors_data_in_the_same_file)
+{
+    auto function = onnx_import::import_onnx_model(file_util::path_join(
+        SERIALIZED_ZOO, "onnx/external_data_two_tensors_data_in_the_same_file.prototxt"));
+
+    auto test_case = test::TestCase<TestEngine>(function);
+    // first input: {3, 2, 1}, second: {1, 2, 3} read from external file
+    test_case.add_input<int32_t>({2, 3, 1});
+
+    test_case.add_expected_output<int32_t>({3, 3, 3});
+    test_case.run();
+}
+
+NGRAPH_TEST(${BACKEND_NAME}, onnx_external_invalid_external_data_exception)
+{
+    try
+    {
+        auto function = onnx_import::import_onnx_model(
+            file_util::path_join(SERIALIZED_ZOO, "onnx/external_data_file_not_found.prototxt"));
+        FAIL() << "Incorrect path to external data not detected";
+    }
+    catch (const ngraph_error& error)
+    {
+        EXPECT_PRED_FORMAT2(
+            testing::IsSubstring,
+            std::string("not_existed_file.data, offset: 4096, data_lenght: 16, sha1_digest: 0)"),
+            error.what());
+    }
+    catch (...)
+    {
+        FAIL() << "Importing onnx model failed for unexpected reason";
+    }
+}