diff --git a/CHANGES.txt b/CHANGES.txt
index 59fd55c..dfcc887 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -14,6 +14,9 @@ Next release
   https://github.com/Pylons/colander/pull/12 , and
   https://github.com/Pylons/colander/issues/2 .
 
+- Invalid.messages() now returns an empty list if there are no messages.
+  See https://github.com/Pylons/colander/pull/21 .
+
 0.9.6 (2012-02-14)
 ------------------
 
diff --git a/colander/__init__.py b/colander/__init__.py
index 8764c29..d4f81a6 100644
--- a/colander/__init__.py
+++ b/colander/__init__.py
@@ -71,13 +71,15 @@ class Invalid(Exception):
         self.children = []
 
     def messages(self):
-        """ Return an iterable of error messages for this exception
-        using the ``msg`` attribute of this error node.  If the
-        ``msg`` attribute is iterable, it is returned.  If it is not
-        iterable, a single-element list containing the ``msg`` value
-        is returned."""
+        """ Return an iterable of error messages for this exception using the
+        ``msg`` attribute of this error node.  If the ``msg`` attribute is
+        iterable, it is returned.  If it is not iterable, and is
+        non-``None``, a single-element list containing the ``msg`` value is
+        returned.  If the value is ``None``, an empty list is returned."""
         if is_nonstr_iter(self.msg):
             return self.msg
+        if self.msg is None:
+            return []
         return [self.msg]
 
     def add(self, exc, pos=None):
diff --git a/colander/tests/test_colander.py b/colander/tests/test_colander.py
index 792d321..9317caa 100644
--- a/colander/tests/test_colander.py
+++ b/colander/tests/test_colander.py
@@ -183,6 +183,11 @@ class TestInvalid(unittest.TestCase):
         exc = self._makeOne(node, 'msg')
         self.assertEqual(exc.messages(), ['msg'])
 
+    def test_messages_msg_None(self):
+        node = DummySchemaNode(None)
+        exc = self._makeOne(node, None)
+        self.assertEqual(exc.messages(), [])
+        
 class TestAll(unittest.TestCase):
     def _makeOne(self, validators):
         from colander import All