diff --git a/jsonnet/kube-prometheus/components/alertmanager.libsonnet b/jsonnet/kube-prometheus/components/alertmanager.libsonnet
index 5e992176db4c1912edb1bdfbbdfc7645203ecc3f..64f670e258c92fb04394bb5572da6c2089a225c7 100644
--- a/jsonnet/kube-prometheus/components/alertmanager.libsonnet
+++ b/jsonnet/kube-prometheus/components/alertmanager.libsonnet
@@ -3,7 +3,10 @@ local defaults = {
   namespace: error 'must provide namespace',
   image: error 'must provide image',
   version: error 'must provide version',
-  resources: {},
+  resources: {
+    limits: { cpu: '100m', memory: '100Mi' },
+    requests: { cpu: '4m', memory: '100Mi' },
+  },
   commonLabels:: {
     'app.kubernetes.io/name': 'alertmanager',
     'app.kubernetes.io/version': defaults.version,