diff --git a/Lib/urllib2.py b/Lib/urllib2.py
index 1984cf2..773cd7d 100644
--- a/Lib/urllib2.py
+++ b/Lib/urllib2.py
@@ -1168,7 +1168,7 @@
         self.max_conns = m
 
     def connect_ftp(self, user, passwd, host, port, dirs):
-        key = user, passwd, host, port
+        key = user, host, port, '/'.join(dirs)
         if key in self.cache:
             self.timeout[key] = time.time() + self.delay
         else: