diff --git a/hgext/mq.py b/hgext/mq.py
--- a/hgext/mq.py
+++ b/hgext/mq.py
@@ -677,7 +677,7 @@
             write = self.ui.warn
 
         if all_patches or self.ui.verbose:
-            if isinstance(idx, str):
+            if isinstance(idx, bytes):
                 idx = self.series.index(idx)
             pushable, why = self.pushable(idx)
             if all_patches and pushable: