diff --git a/tasks/backup.yml b/tasks/backup.yml
index 3a7d85377adeb1da8f723cadebfa501d0a2dd856..9d6aaed7cd00762177510cb38f214f958a6817b6 100644
--- a/tasks/backup.yml
+++ b/tasks/backup.yml
@@ -17,5 +17,5 @@
 - name: add backup cleanup cronjob
   cron:
     name: mongodb backup cleanup
-    job: 'find /opt/mongodbbackup/* -mtime +{{ mongodb.backup.keep_days }} -type f -exec rm {} \;'
+    job: 'find /opt/mongodbbackup/* -mtime +{{ mongodb.backup.keep_days - 1 }} -type f -exec rm {} \;'
     special_time: daily