diff --git a/mcrouter/test/MCProcess.py b/mcrouter/test/MCProcess.py
index 48e3d95c9..a22f52c43 100644
--- a/mcrouter/test/MCProcess.py
+++ b/mcrouter/test/MCProcess.py
@@ -782,7 +782,8 @@ def __init__(self, args, port=None, base_dir=None):
                      '-a', self.async_spool,
                      '--stats-root', self.stats_dir,
                      '--debug-fifo-root', self.debug_fifo_root,
-                     '--rss-limit-mb', '16384'])
+                     '--rss-limit-mb', '16384',
+                     '--fibers-stack-size', '65536'])
 
         listen_sock = None
         pass_fds = []