diff -r eb251e3624df Lib/mimetypes.py
--- a/Lib/mimetypes.py	Fri Jan 24 00:33:25 2014 -0500
+++ b/Lib/mimetypes.py	Fri Jan 24 17:31:16 2014 +0800
@@ -359,13 +359,18 @@
 
 
 def read_mime_types(file):
+    f = None
     try:
         f = open(file)
+        db = MimeTypes()
+        db.readfp(f, True)
     except OSError:
         return None
-    db = MimeTypes()
-    db.readfp(f, True)
-    return db.types_map[True]
+    else:
+        return db.types_map[True]
+    finally:
+        if f is not None:
+            f.close()
 
 
 def _default_mime_types():
diff -r eb251e3624df Lib/test/test_mimetypes.py
--- a/Lib/test/test_mimetypes.py	Fri Jan 24 00:33:25 2014 -0500
+++ b/Lib/test/test_mimetypes.py	Fri Jan 24 17:31:16 2014 +0800
@@ -40,6 +40,19 @@
            ("x-application/x-unittest", None))
         eq(self.db.guess_extension("x-application/x-unittest"), ".pyunit")
 
+    def test_read_mime_types(self):
+        self.addCleanup(support.unlink, support.TESTFN)
+        with open(support.TESTFN, "w") as file:
+            file.write("x-application/mimea mimea\n")
+            file.write("application/mimeb mimeb\n")
+        mime_types = mimetypes.read_mime_types(support.TESTFN)
+        self.assertEqual(mime_types['.mimea'], 'x-application/mimea')
+        self.assertEqual(mime_types['.mimeb'], 'application/mimeb')
+
+    def test_read_mime_types_with_non_existent_file(self):
+        mime_types = mimetypes.read_mime_types('not_an_existing_mime_file')
+        self.assertIsNone(mime_types)
+
     def test_non_standard_types(self):
         eq = self.assertEqual
         # First try strict