diff --git a/djangorestframework/permissions.py b/djangorestframework/permissions.py
index 59c5f481f..0052a6094 100644
--- a/djangorestframework/permissions.py
+++ b/djangorestframework/permissions.py
@@ -73,7 +73,7 @@ class IsAdminUser(BasePermission):
     """
 
     def check_permission(self, user):
-        if not user.is_staff():
+        if not user.is_staff:
             raise _403_FORBIDDEN_RESPONSE