diff --git a/Lib/os.py b/Lib/os.py
index 84eeaeb524d..e4ea1424b92 100644
--- a/Lib/os.py
+++ b/Lib/os.py
@@ -260,7 +260,10 @@ def makedirs(name, mode=0o777, exist_ok=False):
             # be happy if someone already created the path
             if e.errno != errno.EEXIST:
                 raise
-        if tail == curdir:           # xxx/newdir/. exists if xxx/newdir exists
+        cdir = curdir
+        if isinstance(tail, bytes):
+            cdir = bytes(curdir, 'ASCII')
+        if tail == cdir:           # xxx/newdir/. exists if xxx/newdir exists
             return
     try:
         mkdir(name, mode)