diff --git a/jsonnet/kube-prometheus/alertmanager/alertmanager.libsonnet b/jsonnet/kube-prometheus/alertmanager/alertmanager.libsonnet
index bdbe57a21149433ba688cba92076e2d092da94e1..2742b7fef0bd77301649c1bf829a2f14e9192dfa 100644
--- a/jsonnet/kube-prometheus/alertmanager/alertmanager.libsonnet
+++ b/jsonnet/kube-prometheus/alertmanager/alertmanager.libsonnet
@@ -25,7 +25,7 @@ local k = import 'ksonnet/ksonnet.beta.4/k.libsonnet';
           target_match_re: {
             severity: 'warning|info',
           },
-          equal: ['alertname'],
+          equal: ['namespace', 'alertname'],
         }, {
           source_match: {
             severity: 'warning',
@@ -33,7 +33,7 @@ local k = import 'ksonnet/ksonnet.beta.4/k.libsonnet';
           target_match_re: {
             severity: 'info',
           },
-          equal: ['alertname'],
+          equal: ['namespace', 'alertname'],
         }],
         route: {
           group_by: ['namespace'],