diff --git a/usr.bin/grep/file.c b/usr.bin/grep/file.c
index cd276481177..3349b72842c 100644
--- a/usr.bin/grep/file.c
+++ b/usr.bin/grep/file.c
@@ -72,6 +72,8 @@ grep_refill(struct file *f)
 	bufrem = 0;
 
 	nr = read(f->fd, buffer, MAXBUFSIZ);
+	if (nr < 0 && errno == EISDIR)
+		nr = 0;
 	if (nr < 0)
 		return (-1);