diff --git a/opm/parser/eclipse/Parser/Parser.hpp b/opm/parser/eclipse/Parser/Parser.hpp
index 233d75f83..54cc3beb6 100644
--- a/opm/parser/eclipse/Parser/Parser.hpp
+++ b/opm/parser/eclipse/Parser/Parser.hpp
@@ -58,9 +58,9 @@ namespace Opm {
                        ErrorGuard& errors) const;
 
         Deck parseFile(const std::string&,
-                       const ParseContext&);
+                       const ParseContext&) const;
 
-        Deck parseFile(const std::string& datafile);
+        Deck parseFile(const std::string& datafile) const;
 
         Deck parseString(const std::string &data,
                          const ParseContext&,
diff --git a/src/opm/parser/eclipse/Parser/Parser.cpp b/src/opm/parser/eclipse/Parser/Parser.cpp
index c75419598..86ec454ed 100644
--- a/src/opm/parser/eclipse/Parser/Parser.cpp
+++ b/src/opm/parser/eclipse/Parser/Parser.cpp
@@ -941,12 +941,12 @@ bool parseState( ParserState& parserState, const Parser& parser ) {
     }
 
     Deck Parser::parseFile(const std::string& dataFileName,
-                           const ParseContext& parseContext) {
+                           const ParseContext& parseContext) const {
         ErrorGuard errors;
         return this->parseFile(dataFileName, parseContext, errors);
     }
 
-    Deck Parser::parseFile(const std::string& dataFileName) {
+    Deck Parser::parseFile(const std::string& dataFileName) const {
         ErrorGuard errors;
         return this->parseFile(dataFileName, ParseContext(), errors);
     }