diff --git a/git_command.py b/git_command.py
index 259fb02..3095fda 100644
--- a/git_command.py
+++ b/git_command.py
@@ -263,6 +263,8 @@
         if not buf:
           s_in.remove(s)
           continue
+        if not hasattr(buf, 'encode'):
+          buf = buf.decode()
         if s.std_name == 'stdout':
           self.stdout += buf
         else: