diff --git a/src/include/utils/timestamp.h b/src/include/utils/timestamp.h
index 0c6e59cc92f..5fb7529abd5 100644
--- a/src/include/utils/timestamp.h
+++ b/src/include/utils/timestamp.h
@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/utils/timestamp.h,v 1.64 2006/10/04 00:30:11 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/utils/timestamp.h,v 1.64.2.1 2008/01/23 21:26:20 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -182,7 +182,7 @@ typedef double fsec_t;
 #define INTERVAL_RANGE(t) (((t) >> 16) & INTERVAL_RANGE_MASK)
 
 #ifdef HAVE_INT64_TIMESTAMP
-#define TimestampTzPlusMilliseconds(tz,ms) ((tz) + ((ms) * 1000))
+#define TimestampTzPlusMilliseconds(tz,ms) ((tz) + ((ms) * (int64) 1000))
 #else
 #define TimestampTzPlusMilliseconds(tz,ms) ((tz) + ((ms) / 1000.0))
 #endif