diff --git a/greenctld b/greenctld
index b7a94d5..6240eff 100755
--- a/greenctld
+++ b/greenctld
@@ -218,7 +218,7 @@ class TCPServer(object):
             self.close_client(fd)
             return
 
-        self.client_buf[fd] += buf
+        self.client_buf[fd] += buf.decode()
 
         while True:
             cmd, sep, tail = self.client_buf[fd].partition('\n')