diff --git a/src/irclib.py b/src/irclib.py
index bcde29b76..d048753ab 100644
--- a/src/irclib.py
+++ b/src/irclib.py
@@ -908,7 +908,8 @@ class Irc(IrcCommandDispatcher):
                 else:
                     auth_string = base64.b64encode(('%s\x00%s\x00%s' %
                             (self.sasl_username, self.sasl_username,
-                             self.sasl_password)).encode('utf-8'))
+                             self.sasl_password)).encode('utf-8')).decode(
+                            'utf-8')
                     log.debug('Sending CAP REQ command, requesting capability \'sasl\'.')
                     self.queueMsg(ircmsgs.IrcMsg(command="CAP", args=('REQ', 'sasl')))
                     log.debug('Sending AUTHENTICATE command, using mechanism PLAIN.')