diff --git a/requests/sessions.py b/requests/sessions.py
index fe0a84e1..bb188812 100644
--- a/requests/sessions.py
+++ b/requests/sessions.py
@@ -182,7 +182,7 @@ class Session(SessionRedirectMixin):
     __attrs__ = [
         'headers', 'cookies', 'auth', 'timeout', 'proxies', 'hooks',
         'params', 'verify', 'cert', 'prefetch', 'adapters', 'stream',
-        'trust_env']
+        'trust_env', 'max_redirects']
 
     def __init__(self):