diff --git a/lib/isc/unix/stdtime.c b/lib/isc/unix/stdtime.c
index a68ad31b17..80e9f25547 100644
--- a/lib/isc/unix/stdtime.c
+++ b/lib/isc/unix/stdtime.c
@@ -45,7 +45,7 @@ isc_stdtime_get(isc_stdtime_t *t) {
 				strbuf);
 	}
 
-	REQUIRE(ts.tv_sec > 0 && ts.tv_nsec > 0 && ts.tv_nsec < NS_PER_S);
+	REQUIRE(ts.tv_sec > 0 && ts.tv_nsec >= 0 && ts.tv_nsec < NS_PER_S);
 
 	*t = (unsigned int)ts.tv_sec;
 }