diff --git a/mock/mock.py b/mock/mock.py
index 1db1b4f..d2c469b 100644
--- a/mock/mock.py
+++ b/mock/mock.py
@@ -2059,8 +2059,15 @@
     message = '%s(%%s)' % name
     formatted_args = ''
     args_string = ', '.join([repr(arg) for arg in args])
+
+    def encode_item(item):
+        if six.PY2 and isinstance(item, unicode):
+            return item.encode("utf-8")
+        else:
+            return item
+
     kwargs_string = ', '.join([
-        '%s=%r' % (key, value) for key, value in sorted(kwargs.items())
+        '%s=%r' % (encode_item(key), value) for key, value in sorted(kwargs.items())
     ])
     if args_string:
         formatted_args = args_string
diff --git a/mock/tests/testhelpers.py b/mock/tests/testhelpers.py
index d96dbf4..a87df1b 100644
--- a/mock/tests/testhelpers.py
+++ b/mock/tests/testhelpers.py
@@ -928,6 +928,20 @@
         self.assertEqual(str(mock.mock_calls), expected)
 
 
+    @unittest.skipIf(six.PY3, "Unicode is properly handled with Python 3")
+    def test_call_list_unicode(self):
+        # See github issue #328
+        mock = Mock()
+
+        class NonAsciiRepr(object):
+            def __repr__(self):
+                return "\xe9"
+
+        mock(**{unicode("a"): NonAsciiRepr()})
+
+        self.assertEqual(str(mock.mock_calls), "[call(a=\xe9)]")
+
+
     def test_propertymock(self):
         p = patch('%s.SomeClass.one' % __name__, new_callable=PropertyMock)
         mock = p.start()