diff --git a/roles/prometheus/templates/prometheus/alert.rules.yml.j2 b/roles/prometheus/templates/prometheus/alert.rules.yml.j2
index 2b358276..f032a8e2 100644
--- a/roles/prometheus/templates/prometheus/alert.rules.yml.j2
+++ b/roles/prometheus/templates/prometheus/alert.rules.yml.j2
@@ -159,6 +159,14 @@ groups:
     annotations:
       summary: "{{ $value }} paquet(s) APT sont inutile(s) sur {{ $labels.instance }}."
 
+  - alert: MailqNotEmpty
+    expr: postfix_mailq_length > 5
+    for: 1m
+    labels:
+      severity: warning
+    annotations:
+      summary: "{{ $value }} mails dans la mailq sur {{ $labels.instance }}."
+
   # NTP (need NTP plugin in node)
 #  - alert: ntp_drifting
 #    expr: node_ntp_drift_seconds > 0.05