diff --git a/lib/py/src/protocol/TBinaryProtocol.py b/lib/py/src/protocol/TBinaryProtocol.py
index c089ac5..860f461 100644
--- a/lib/py/src/protocol/TBinaryProtocol.py
+++ b/lib/py/src/protocol/TBinaryProtocol.py
@@ -70,7 +70,7 @@
     otrans.write(buff)
     
   def writeI64(self, otrans, i64):
-    buff = pack("!l", i64)
+    buff = pack("!q", i64)
     otrans.write(buff)
 
   def writeString(self, otrans, str):
@@ -150,7 +150,7 @@
 
   def readI64(self, itrans):
     buff = itrans.readAll(8)
-    val, = unpack('!l', buff)
+    val, = unpack('!q', buff)
     return val
 
   def readString(self, itrans):