diff --git a/django/contrib/admin/widgets.py b/django/contrib/admin/widgets.py
index e2cd2113f8..291bee0b05 100644
--- a/django/contrib/admin/widgets.py
+++ b/django/contrib/admin/widgets.py
@@ -131,10 +131,10 @@ class ForeignKeyRawIdWidget(forms.TextInput):
             items = []
             for k, v in self.rel.limit_choices_to.items():
                 if isinstance(v, list):
-                    v = [str(x) for x in v]
+                    v = ','.join([str(x) for x in v])
                 else:
                     v = str(v)
-                items.append((k, ','.join(v)))
+                items.append((k, v))
             params.update(dict(items))
         return params