diff --git a/pylons_app/config/middleware.py b/pylons_app/config/middleware.py
--- a/pylons_app/config/middleware.py
+++ b/pylons_app/config/middleware.py
@@ -49,9 +49,10 @@ def make_app(global_conf, full_stack = T
         # Display error documents for 401, 403, 404 status codes (and
         # 500 when debug is disabled)
         if asbool(config['debug']):
-            app = StatusCodeRedirect(app)
+            #don't handle 404, since mercurial does it for us.
+            app = StatusCodeRedirect(app, [400, 401, 403, 500])
         else:
-            app = StatusCodeRedirect(app, [400, 401, 403, 404, 500])
+            app = StatusCodeRedirect(app, [400, 401, 403, 500])
 
     # Establish the Registry for this application
     app = RegistryManager(app)