diff --git a/usr.bin/xargs/xargs.c b/usr.bin/xargs/xargs.c
--- a/usr.bin/xargs/xargs.c
+++ b/usr.bin/xargs/xargs.c
@@ -229,6 +229,8 @@
 		Rflag = 5;
 	if (Iflag && !Sflag)
 		Sflag = 255;
+	if (Iflag && nflag)
+		warnx("-I and -n are mutually exclusive.  Ignoring -n value");
 	if (xflag && !nflag)
 		usage();
 	if (Iflag || Lflag)