diff --git a/usr.bin/killall/killall.1 b/usr.bin/killall/killall.1
index 4c2ecaf07f90..bb10e9483c15 100644
--- a/usr.bin/killall/killall.1
+++ b/usr.bin/killall/killall.1
@@ -32,7 +32,7 @@
 .Nd kill processes by name
 .Sh SYNOPSIS
 .Nm
-.Op Fl dlmsvz
+.Op Fl delmsvz
 .Op Fl help
 .Op Fl j Ar jid
 .Op Fl u Ar user
@@ -63,6 +63,11 @@ Be more verbose about what will be done.  For a single
 option, a list of the processes that will be sent the signal will be
 printed, or a message indicating that no matching processes have been
 found.
+.It Fl e
+Use the effective user id instead of the (default) real user id for matching
+processes specified with the
+.Fl u
+option.
 .It Fl help
 Give a help on the command usage and exit.
 .It Fl l
diff --git a/usr.bin/killall/killall.c b/usr.bin/killall/killall.c
index 6d1596903a58..be3b9697d778 100644
--- a/usr.bin/killall/killall.c
+++ b/usr.bin/killall/killall.c
@@ -50,7 +50,7 @@ static void __dead2
 usage(void)
 {
 
-	fprintf(stderr, "usage: killall [-dlmsvz] [-help] [-j jid]\n");
+	fprintf(stderr, "usage: killall [-delmsvz] [-help] [-j jid]\n");
 	fprintf(stderr,
 	    "               [-u user] [-t tty] [-c cmd] [-SIGNAL] [cmd]...\n");
 	fprintf(stderr, "At least one option or argument to specify processes must be given.\n");
@@ -113,6 +113,7 @@ main(int ac, char **av)
 	int		vflag = 0;
 	int		sflag = 0;
 	int		dflag = 0;
+	int		eflag = 0;
 	int		jflag = 0;
 	int		mflag = 0;
 	int		zflag = 0;
@@ -192,6 +193,9 @@ main(int ac, char **av)
 			case 'd':
 				dflag++;
 				break;
+			case 'e':
+				eflag++;
+				break;
 			case 'm':
 				mflag++;
 				break;
@@ -272,7 +276,7 @@ main(int ac, char **av)
 	miblen = 3;
 
 	if (user) {
-		mib[2] = KERN_PROC_RUID;
+		mib[2] = eflag ? KERN_PROC_UID : KERN_PROC_RUID;
 		mib[3] = uid;
 		miblen = 4;
 	} else if (tty) {
@@ -313,7 +317,10 @@ main(int ac, char **av)
 		strncpy(thiscmd, procs[i].ki_comm, MAXCOMLEN);
 		thiscmd[MAXCOMLEN] = '\0';
 		thistdev = procs[i].ki_tdev;
-		thisuid = procs[i].ki_ruid;	/* real uid */
+		if (eflag)
+			thisuid = procs[i].ki_uid;	/* effective uid */
+		else
+			thisuid = procs[i].ki_ruid;	/* real uid */
 
 		if (thispid == mypid)
 			continue;