diff --git a/lib/datasource/packagist.js b/lib/datasource/packagist.js
index eee94575f9978eac10a49d34de25d711c8828fd5..834ae5bc5ac3f360dc20a19ac8167eeffdc500c4 100644
--- a/lib/datasource/packagist.js
+++ b/lib/datasource/packagist.js
@@ -25,7 +25,7 @@ function getHostOpts(url) {
 
 async function getRegistryMeta(regUrl) {
   try {
-    const url = URL.resolve(regUrl, 'packages.json');
+    const url = URL.resolve(regUrl.replace(/\/?$/, '/'), 'packages.json');
     const opts = getHostOpts(url);
     const res = (await got(url, opts)).body;
     const meta = {};