diff --git a/django/middleware/common.py b/django/middleware/common.py
index a564017ed6..270ab995bb 100644
--- a/django/middleware/common.py
+++ b/django/middleware/common.py
@@ -54,7 +54,7 @@ class CommonMiddleware(object):
         # trailing slash and there is no pattern for the current path
         if settings.APPEND_SLASH and (not old_url[1].endswith('/')):
             try:
-                urlresolvers.resolve(request.path)
+                urlresolvers.resolve(request.path_info)
             except urlresolvers.Resolver404:
                 new_url[1] = new_url[1] + '/'
                 if settings.DEBUG and request.method == 'POST':
@@ -69,7 +69,7 @@ class CommonMiddleware(object):
         if new_url != old_url:
             # Redirect if the target url exists
             try:
-                urlresolvers.resolve(new_url[1])
+                urlresolvers.resolve("%s/" % request.path_info)
             except urlresolvers.Resolver404:
                 pass
             else:
diff --git a/tests/regressiontests/middleware/tests.py b/tests/regressiontests/middleware/tests.py
index 5e7fd320d6..3252971253 100644
--- a/tests/regressiontests/middleware/tests.py
+++ b/tests/regressiontests/middleware/tests.py
@@ -12,7 +12,7 @@ class CommonMiddlewareTest(TestCase):
             'SERVER_NAME': 'testserver',
             'SERVER_PORT': 80,
         }
-        request.path = "/middleware/%s" % path
+        request.path = request.path_info = "/middleware/%s" % path
         return request
 
     def test_append_slash_have_slash(self):