diff --git a/CHANGES.txt b/CHANGES.txt
index da671352..5ff7ec70 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -1,6 +1,12 @@
 Changes
 =======
 
+Next release
+------------
+
+- Allow the use of 'missing=None' for Number.  See
+  https://github.com/Pylons/colander/pull/59 .
+
 0.9.8 (2012-04-27)
 ------------------
 
diff --git a/colander/__init__.py b/colander/__init__.py
index 260db5e1..a37b2730 100644
--- a/colander/__init__.py
+++ b/colander/__init__.py
@@ -951,7 +951,7 @@ class Number(SchemaType):
     num = None
 
     def serialize(self, node, appstruct):
-        if not appstruct:
+        if appstruct in (null, None):
             return null
 
         try:
diff --git a/colander/tests/test_colander.py b/colander/tests/test_colander.py
index 05f986c5..229c97f0 100644
--- a/colander/tests/test_colander.py
+++ b/colander/tests/test_colander.py
@@ -1192,6 +1192,13 @@ def test_serialize_ok(self):
         result = typ.serialize(node, val)
         self.assertEqual(result, '1')
 
+    def test_serialize_zero(self):
+        val = 0
+        node = DummySchemaNode(None)
+        typ = self._makeOne()
+        result = typ.serialize(node, val)
+        self.assertEqual(result, '0')
+
 class TestFloat(unittest.TestCase):
     def _makeOne(self):
         from colander import Float
diff --git a/setup.py b/setup.py
index c75ef492..42b643b7 100644
--- a/setup.py
+++ b/setup.py
@@ -32,7 +32,7 @@
 docs_extras = ['Sphinx']
 
 setup(name='colander',
-      version='0.9.8',
+      version='0.9.9dev1',
       description=('A simple schema-based serialization and deserialization '
                    'library'),
       long_description=README + '\n\n' +  CHANGES,