diff --git a/Makefile b/Makefile
index a03a95c..3f254a5 100644
--- a/Makefile
+++ b/Makefile
@@ -20,6 +20,9 @@ options:
 config.h:
 	cp config.def.h $@
 
+config.mk: config.def.mk
+	cp config.def.mk $@
+
 $(OBJ): arg.h config.h config.mk drw.h
 
 dmenu: dmenu.o drw.o util.o