diff --git a/runbot_merge/models/pull_requests.py b/runbot_merge/models/pull_requests.py
index e07f3f02..99188d1a 100644
--- a/runbot_merge/models/pull_requests.py
+++ b/runbot_merge/models/pull_requests.py
@@ -693,6 +693,8 @@ class Batch(models.Model):
                 msg = commit['message']
                 author = commit['author']
 
+            msg += '\n\ncloses {pr.repository.name}#{pr.number}'.format(pr=pr)
+
             try:
                 new_heads[pr] = gh.merge(pr.head, 'tmp.{}'.format(pr.target.name), msg, squash=pr.squash, author=author)['sha']
             except exceptions.MergeError:
diff --git a/runbot_merge/tests/test_basic.py b/runbot_merge/tests/test_basic.py
index 5fb18fb6..e834215c 100644
--- a/runbot_merge/tests/test_basic.py
+++ b/runbot_merge/tests/test_basic.py
@@ -78,6 +78,7 @@ def test_trivial_flow(env, repo):
         'a': b'some other content',
         'b': b'a second file',
     }
+    assert master.message, "gibberish\n\nblahblah\n\ncloses odoo/odoo#1"
 
 def test_staging_conflict(env, repo):
     # create base branch