diff --git a/AUTHORS b/AUTHORS
index a0032f5..ceb303e 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -141,6 +141,7 @@ answer newbie questions, and generally made Django that much better:
     Sung-Jin Hong <serialx.net@gmail.com>
     Richard House <Richard.House@i-logue.com>
     Robert Rock Howard <http://djangomojo.com/>
+    Rob Hudson <http://rob.cogit8.org/>
     Jason Huggins <http://www.jrandolph.com/blog/>
     Hyun Mi Ae
     Tom Insam
diff --git a/django/contrib/contenttypes/management.py b/django/contrib/contenttypes/management.py
index cb52e08..54a4459 100644
--- a/django/contrib/contenttypes/management.py
+++ b/django/contrib/contenttypes/management.py
@@ -1,28 +1,37 @@
-"""
-Creates content types for all installed models.
-"""
-
+from django.contrib.contenttypes.models import ContentType
 from django.dispatch import dispatcher
 from django.db.models import get_apps, get_models, signals
 from django.utils.encoding import smart_unicode
 
 def create_contenttypes(app, created_models, verbosity=2):
-    from django.contrib.contenttypes.models import ContentType
+    """
+    Creates content types for models in the given app, removing any models that
+    appear to be orphaned.
+    """
     ContentType.objects.clear_cache()
+    content_types = list(ContentType.objects.filter(app_label=app.__name__.split('.')[-2]))
     app_models = get_models(app)
     if not app_models:
         return
     for klass in app_models:
         opts = klass._meta
         try:
-            ContentType.objects.get(app_label=opts.app_label,
-                model=opts.object_name.lower())
+            ct = ContentType.objects.get(app_label=opts.app_label,
+                                         model=opts.object_name.lower())
+            content_types.remove(ct)
         except ContentType.DoesNotExist:
             ct = ContentType(name=smart_unicode(opts.verbose_name_raw),
                 app_label=opts.app_label, model=opts.object_name.lower())
             ct.save()
             if verbosity >= 2:
                 print "Adding content type '%s | %s'" % (ct.app_label, ct.model)
+    # The presence of any remaining content types means the supplied app has an
+    # undefined model and can safely be removed, which cascades to also remove
+    # related permissions.
+    for ct in content_types:
+        if verbosity >= 2:
+            print "Deleting stale content type '%s | %s'" % (ct.app_label, ct.model)
+        ct.delete()
 
 def create_all_contenttypes(verbosity=2):
     for app in get_apps():