diff --git a/lib/platform/github/index.js b/lib/platform/github/index.js
index c2e232a1ec05d75e14f140cd0ee647b06c202483..285281cc53737366733940ad402103d84f5f6e7a 100644
--- a/lib/platform/github/index.js
+++ b/lib/platform/github/index.js
@@ -693,7 +693,7 @@ async function getPr(prNo) {
       // Check if only one author of all commits
       logger.debug('Checking all commits');
       const prCommits = (await get(
-        `repos/${config.repoName}/pulls/${prNo}/commits`
+        `repos/${config.parentRepo || config.repoName}/pulls/${prNo}/commits`
       )).body;
       const authors = prCommits.reduce((arr, commit) => {
         logger.trace({ commit }, `Checking commit`);