diff --git a/protobuf/Makefile b/protobuf/Makefile
index 9a9ba2290..f2a57caf6 100644
--- a/protobuf/Makefile
+++ b/protobuf/Makefile
@@ -61,7 +61,7 @@ $(PROTO_LIBRARY): $(PROTO_OBJS)
 
 .PHONY: protobuf
 
-protobuf: $(PROTO_LIBRARY)
+protobuf: $(PROTO_LIBRARY) $(PROTO_SRCS) $(PROTO_HDRS)
 
 clean:
 	$(E) "  CLEAN PROTOBUF"