diff --git a/rest_framework/response.py b/rest_framework/response.py
index 3f038e3b5..0e97668eb 100644
--- a/rest_framework/response.py
+++ b/rest_framework/response.py
@@ -98,7 +98,7 @@ class Response(SimpleTemplateResponse):
         state = super(Response, self).__getstate__()
         for key in (
             'accepted_renderer', 'renderer_context', 'resolver_match',
-            'client', 'request', 'wsgi_request'
+            'client', 'request', 'json', 'wsgi_request'
         ):
             if key in state:
                 del state[key]