diff --git a/django/core/meta/__init__.py b/django/core/meta/__init__.py
index eaa69b960b..916ce42aa1 100644
--- a/django/core/meta/__init__.py
+++ b/django/core/meta/__init__.py
@@ -1134,6 +1134,14 @@ def method_get_many_to_many(field_with_rel, self):
 # Handles setting many-to-many relationships.
 # Example: Poll.set_sites()
 def method_set_many_to_many(rel_field, self, id_list):
+    if len(id_list) == 1 and isinstance(id_list[0], basestring) and ',' in id_list[0]:
+        new_id_list = []
+        for bit in id_list[0].split(','):
+            try:
+                new_id_list.append(int(bit.strip()))
+            except ValueError:
+                continue
+        id_list = new_id_list
     current_ids = [getattr(obj, obj._meta.pk.attname) for obj in method_get_many_to_many(rel_field, self)]
     ids_to_add, ids_to_delete = dict([(i, 1) for i in id_list]), []
     for current_id in current_ids: