diff --git a/usr.bin/renice/renice.8 b/usr.bin/renice/renice.8
index 56d431ef91da..fc349d1c9e36 100644
--- a/usr.bin/renice/renice.8
+++ b/usr.bin/renice/renice.8
@@ -63,7 +63,7 @@ scheduling priority of one or more running processes.
 The following
 .Ar who
 parameters are interpreted as process ID's, process group
-ID's, or user names.
+ID's, user ID's or user names.
 .Nm Renice Ns 'ing
 a process group causes all processes in the process group
 to have their scheduling priority altered.
@@ -87,7 +87,7 @@ the current priority of each process.
 .It Fl u
 Force the
 .Ar who
-parameters to be interpreted as user names.
+parameters to be interpreted as user names or user ID's.
 .It Fl p
 Resets the
 .Ar who
diff --git a/usr.bin/renice/renice.c b/usr.bin/renice/renice.c
index effa8cf507f7..71c7087faa34 100644
--- a/usr.bin/renice/renice.c
+++ b/usr.bin/renice/renice.c
@@ -102,12 +102,14 @@ main(int argc, char *argv[])
 			continue;
 		}
 		if (which == PRIO_USER) {
-			pwd = getpwnam(*argv);
-			if (pwd == NULL) {
-				warnx("%s: unknown user", *argv);
+			if ((pwd = getpwnam(*argv)) != NULL)
+				who = pwd->pw_uid;
+			else if (getnum("uid", *argv, &who))
+				continue;
+			else if (who < 0) {
+				warnx("%s: bad value", *argv);
 				continue;
 			}
-			who = pwd->pw_uid;
 		} else {
 			if (getnum("pid", *argv, &who))
 				continue;