diff --git a/src/common/jingle_ftstates.py b/src/common/jingle_ftstates.py
index 3d5d6b9dc..5c305f78a 100644
--- a/src/common/jingle_ftstates.py
+++ b/src/common/jingle_ftstates.py
@@ -146,7 +146,7 @@ class StateTransfering(JingleFileTransferStates):
 
     def _start_ibb_transfer(self, con):
         self.jft.file_props.transport_sid = self.jft.transport.sid
-        fp = open(self.jft.file_props.file_name, 'r')
+        fp = open(self.jft.file_props.file_name, 'rb')
         con.OpenStream(self.jft.file_props.sid, self.jft.session.peerjid, fp,
                        blocksize=4096)
 
diff --git a/src/common/protocol/bytestream.py b/src/common/protocol/bytestream.py
index be4adcab2..1f6ec2bbd 100644
--- a/src/common/protocol/bytestream.py
+++ b/src/common/protocol/bytestream.py
@@ -251,7 +251,7 @@ class ConnectionBytestream:
         if field.getValue() == nbxmpp.NS_IBB:
             sid = file_props.sid
             file_props.transport_sid = sid
-            fp = open(file_props.file_name, 'r')
+            fp = open(file_props.file_name, 'rb')
             self.OpenStream(sid, file_props.receiver, fp)
             raise nbxmpp.NodeProcessed
 
@@ -815,7 +815,7 @@ class ConnectionIBBytestream(ConnectionBytestream):
             file_props.disconnect_cb = None
             file_props.continue_cb = None
             file_props.syn_id = stanza.getID()
-            file_props.fp = open(file_props.file_name, 'w')
+            file_props.fp = open(file_props.file_name, 'wb')
         conn.send(rep)
 
     def CloseIBBStream(self, file_props):