diff --git a/src/common/util.c b/src/common/util.c
index a69ea33d082c26a24914a6c7303bfed4f065c221..d05c308fe88077fc2d36b18dc16c1f3c1f94ec44 100644
--- a/src/common/util.c
+++ b/src/common/util.c
@@ -1055,7 +1055,7 @@ tv_to_msec(const struct timeval *tv)
 {
   int64_t conv = ((int64_t)tv->tv_sec)*1000L;
   /* Round ghetto-style */
-  conv += (tv->tv_usec+500)/1000L;
+  conv += ((int64_t)tv->tv_usec+500)/1000L;
   return conv;
 }