diff --git a/lib/libmd/Makefile b/lib/libmd/Makefile
index ee1274cbd1df..be53c88f883b 100644
--- a/lib/libmd/Makefile
+++ b/lib/libmd/Makefile
@@ -82,4 +82,18 @@ test:	md2.ref md4.ref md5.ref
 
 beforedepend:	md2hl.c md4hl.c md5hl.c
 
+beforeinstall:
+	-cd ${.CURDIR}; cmp -s md2.h ${DESTDIR}/usr/include/md2.h > \
+	  /dev/null 2>&1 || \
+	  install -c -o ${BINOWN} -g ${BINGRP} -m 444 md2.h \
+	  ${DESTDIR}/usr/include
+	-cd ${.CURDIR}; cmp -s md4.h ${DESTDIR}/usr/include/md4.h > \
+	  /dev/null 2>&1 || \
+	  install -c -o ${BINOWN} -g ${BINGRP} -m 444 md4.h \
+	  ${DESTDIR}/usr/include
+	-cd ${.CURDIR}; cmp -s md5.h ${DESTDIR}/usr/include/md5.h > \
+	  /dev/null 2>&1 || \
+	  install -c -o ${BINOWN} -g ${BINGRP} -m 444 md5.h \
+	  ${DESTDIR}/usr/include
+
 .include <bsd.lib.mk>