diff --git a/CHANGES b/CHANGES
index 59e44e404..473a99b4d 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,6 +1,8 @@
 Release 0.6.3 (in development)
 ==============================
 
+* Properly add C module filenames as dependencies in autodoc.
+
 * #253: Ignore graphviz directives without content instead of
   raising an unhandled exception.
 
diff --git a/sphinx/ext/autodoc.py b/sphinx/ext/autodoc.py
index 155c5711a..ea9a8f17d 100644
--- a/sphinx/ext/autodoc.py
+++ b/sphinx/ext/autodoc.py
@@ -625,6 +625,9 @@ class Documenter(object):
         except PycodeError, err:
             # no source file -- e.g. for builtin and C modules
             self.analyzer = None
+            # at least add the module.__file__ as a dependency
+            if hasattr(self.module, '__file__') and self.module.__file__:
+                self.directive.filename_set.add(self.module.__file__)
         else:
             self.directive.filename_set.add(self.analyzer.srcname)