diff --git a/libsrc/Makefile b/libsrc/Makefile
index 2bc107ad1..e74d3c3a9 100644
--- a/libsrc/Makefile
+++ b/libsrc/Makefile
@@ -265,7 +265,7 @@ plus4lib:
 
 .PHONY: clean
 clean:
-	@for i in cbm common conio dbg em joystick runtime tgi $(ALLTARGETS); do\
+	@for i in cbm common conio dbg em joystick runtime serial tgi $(ALLTARGETS); do\
        	   $(MAKE) -C $$i clean;			      			\
 	done