Index: usr.bin/diff/diffreg.c
===================================================================
--- usr.bin/diff/diffreg.c
+++ usr.bin/diff/diffreg.c
@@ -408,7 +408,8 @@
 	}
 
 	if (diff_format == D_BRIEF && ignore_pats == NULL &&
-	    (flags & (D_FOLDBLANKS|D_IGNOREBLANKS|D_IGNORECASE|D_STRIPCR)) == 0)
+	    (flags & (D_FOLDBLANKS|D_IGNOREBLANKS|D_IGNORECASE|
+	    D_SKIPBLANKLINES|D_STRIPCR)) == 0)
 	{
 		rval = D_DIFFER;
 		status |= 1;
Index: usr.bin/diff/tests/diff_test.sh
===================================================================
--- usr.bin/diff/tests/diff_test.sh
+++ usr.bin/diff/tests/diff_test.sh
@@ -11,6 +11,7 @@
 atf_test_case b230049
 atf_test_case stripcr_o
 atf_test_case b252515
+atf_test_case b278988
 atf_test_case Bflag
 atf_test_case Nflag
 atf_test_case tabsize
@@ -89,6 +90,15 @@
 		diff -qw b252515_a.in b252515_b.in
 }
 
+b278988_body()
+{
+	printf 'a\nb\nn' > b278988.a.in
+	printf 'a\n\nb\nn' > b278988.b.in
+	atf_check -o empty -s eq:0 \
+		diff -Bw b278988.a.in b278988.b.in
+
+}
+
 header_body()
 {
 	export TZ=UTC
@@ -369,6 +379,7 @@
 	atf_add_test_case b230049
 	atf_add_test_case stripcr_o
 	atf_add_test_case b252515
+	atf_add_test_case b278988
 	atf_add_test_case Bflag
 	atf_add_test_case Nflag
 	atf_add_test_case tabsize