diff --git a/oauth2client/client.py b/oauth2client/client.py
index 3527a48..e972564 100644
--- a/oauth2client/client.py
+++ b/oauth2client/client.py
@@ -208,7 +208,8 @@
         d = simplejson.loads(content)
         if 'error' in d:
           self._invalid = True
-          self.store(self)
+          if self.store is not None:
+            self.store(self)
       except:
         pass
       logging.error('Failed to retrieve access token: %s' % content)