diff --git a/rest_framework/permissions.py b/rest_framework/permissions.py
index a48058e66..84215ab33 100644
--- a/rest_framework/permissions.py
+++ b/rest_framework/permissions.py
@@ -46,7 +46,7 @@ class IsAuthenticated(BasePermission):
     """
 
     def has_permission(self, request, view):
-        return request.user and request.user.is_authenticated
+        return request.user and request.user.is_authenticated()
 
 
 class IsAdminUser(BasePermission):