diff -r 9f9ae5f7c4ae Lib/imaplib.py
--- a/Lib/imaplib.py	Tue Dec 17 21:27:56 2013 -0500
+++ b/Lib/imaplib.py	Wed Dec 18 09:30:16 2013 -0500
@@ -824,6 +824,8 @@
                              (name, self.state,
                               ', '.join(Commands[name])))
 
+        self._check_bye()
+
         for typ in ('OK', 'NO', 'BAD'):
             if typ in self.untagged_responses:
                 del self.untagged_responses[typ]