diff --git a/mailbot/mailbot.py b/mailbot/mailbot.py
index b9520f3..35e8712 100644
--- a/mailbot/mailbot.py
+++ b/mailbot/mailbot.py
@@ -59,7 +59,7 @@ def process_messages(self):
 
         for uid, msg in messages.items():
             self.mark_processing(uid)
-            message = message_from_string(msg['RFC822'])
+            message = message_from_string(msg[b'RFC822'].decode('utf-8'))
             for callback_class, rules in CALLBACKS_MAP.items():
                 self.process_message(message, callback_class, rules)
             self.mark_processed(uid)