diff --git a/collabwrapper.py b/collabwrapper.py
index 350d7ba..44ccfcf 100644
--- a/collabwrapper.py
+++ b/collabwrapper.py
@@ -737,7 +737,7 @@ def __init__(self, buddy, conn, blob, filename, description, mime):
         _BaseOutgoingTransfer.__init__(
             self, buddy, conn, filename, description, mime)
 
-        self._blob = blob
+        self._blob = blob.encode('utf-8')
         self._create_channel(len(self._blob))
 
     def _get_input_stream(self):