diff --git a/dist/rules/mongodb/percona-mongodb-exporter.yml b/dist/rules/mongodb/percona-mongodb-exporter.yml
index 07fd367..3e1e5e9 100644
--- a/dist/rules/mongodb/percona-mongodb-exporter.yml
+++ b/dist/rules/mongodb/percona-mongodb-exporter.yml
@@ -23,7 +23,7 @@ groups:
         description: "MongoDB replica member is not healthy\n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}"
 
     - alert: MongodbReplicationLag
-      expr: 'mongodb_rs_members_optimeDate{member_state="PRIMARY"} - on (set) group_right mongodb_rs_members_optimeDate{member_state="SECONDARY"} > 10'
+      expr: '(mongodb_rs_members_optimeDate{member_state="PRIMARY"} - on (set) group_right mongodb_rs_members_optimeDate{member_state="SECONDARY"}) / 1000 > 10'
       for: 0m
       labels:
         severity: critical