diff --git a/core/roslib/src/roslib/message.py b/core/roslib/src/roslib/message.py
index 0317945c..917a877e 100644
--- a/core/roslib/src/roslib/message.py
+++ b/core/roslib/src/roslib/message.py
@@ -46,6 +46,7 @@ import struct
 import sys
 
 import roslib.names
+import genpy
 from genpy import Time, Duration, TVal
 
 # common struct pattern singletons for msgs to use. Although this