diff --git a/lib/api/gitlab.js b/lib/api/gitlab.js
index 192d88641046e316c0f21ed12f2b236445056dae..ecae60fdd39081e102ebd29851a72720bce5f6dd 100644
--- a/lib/api/gitlab.js
+++ b/lib/api/gitlab.js
@@ -164,6 +164,7 @@ async function createPr(branchName, title, body) {
     body: {
       source_branch: branchName,
       target_branch: config.defaultBranch,
+      remove_source_branch: true,
       title,
       description: body,
     },