diff --git a/man3/strstr.3 b/man3/strstr.3
index e085409c2..41ee87489 100644
--- a/man3/strstr.3
+++ b/man3/strstr.3
@@ -61,6 +61,14 @@ but ignores the case of both arguments.
 .SH RETURN VALUE
 These functions return a pointer to the beginning of the
 located substring, or NULL if the substring is not found.
+.PP
+Note the special case:
+If
+.I needle
+is the empty string,
+the return value is always
+.I haystack
+itself.
 .SH ATTRIBUTES
 For an explanation of the terms used in this section, see
 .BR attributes (7).