diff --git a/Makefile b/Makefile
index 8cfbe582d9d74be3bbb648b978b550ccfea8c181..d6165414ca2391bc26817af440fffe86f181147a 100644
--- a/Makefile
+++ b/Makefile
@@ -5,6 +5,7 @@ install:
 	chmod 755 /usr/local/bin/ssl-ca
 
 clean:
+	[ -f .server.pid ] && kill "$$(cat .server.pid)"
 	rm -rf openssl.cnf certs keys CA.key CA.crt CA.p12 CA.srl .server.pid
 
 test: clean