diff --git a/DDSegmentation/include/DDSegmentation/BitField64.h b/DDSegmentation/include/DDSegmentation/BitField64.h
index e5c3992cf63a4bcf1548c78f27f00852a640df0b..006e13cf7b8947145a77cd49d6204697d638d5dc 100644
--- a/DDSegmentation/include/DDSegmentation/BitField64.h
+++ b/DDSegmentation/include/DDSegmentation/BitField64.h
@@ -82,7 +82,7 @@ namespace DDSegmentation {
      */
     void  setValue(unsigned lowWord, unsigned highWord ) {
 
-      setValue( ( lowWord & 0xffffffffUL ) |  ( ( highWord & 0xffffffffUL ) << 32 ) ) ; 
+      setValue( ( lowWord & 0xffffffffULL ) |  ( ( highWord & 0xffffffffULL ) << 32 ) ) ; 
     }
     
     /** Operator for setting a new value and accessing the BitField directly */