diff --git a/Makefile b/Makefile
index 77bcbc0..3b4669f 100644
--- a/Makefile
+++ b/Makefile
@@ -22,6 +22,9 @@ ${OBJ}: config.h config.mk
 config.h:
 	cp config.def.h $@
 
+config.mk: config.def.mk
+	cp config.def.mk $@
+
 dwm: ${OBJ}
 	${CC} -o $@ ${OBJ} ${LDFLAGS}