diff --git a/cmd/prometheus/config.go b/cmd/prometheus/config.go
index 4bc249880c..5ed3e9061c 100644
--- a/cmd/prometheus/config.go
+++ b/cmd/prometheus/config.go
@@ -26,6 +26,7 @@ import (
 	"unicode"
 
 	"github.com/asaskevich/govalidator"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/log"
 	"github.com/prometheus/common/model"
 	"github.com/prometheus/prometheus/config"
@@ -56,6 +57,9 @@ var cfg = struct {
 	prometheusURL    string
 }{
 	alertmanagerURLs: stringset{},
+	notifier: notifier.Options{
+		Registerer: prometheus.DefaultRegisterer,
+	},
 }
 
 // Value type for flags that are now unused, but which are kept around to
diff --git a/cmd/prometheus/main.go b/cmd/prometheus/main.go
index f513338632..c59295861e 100644
--- a/cmd/prometheus/main.go
+++ b/cmd/prometheus/main.go
@@ -97,7 +97,7 @@ func Main() int {
 	reloadables = append(reloadables, remoteStorage)
 
 	var (
-		notifier       = notifier.New(&cfg.notifier, prometheus.DefaultRegisterer)
+		notifier       = notifier.New(&cfg.notifier)
 		targetManager  = retrieval.NewTargetManager(sampleAppender)
 		queryEngine    = promql.NewEngine(localStorage, &cfg.queryEngine)
 		ctx, cancelCtx = context.WithCancel(context.Background())
diff --git a/notifier/notifier.go b/notifier/notifier.go
index abff02a907..54f5d02f3d 100644
--- a/notifier/notifier.go
+++ b/notifier/notifier.go
@@ -74,6 +74,8 @@ type Options struct {
 	RelabelConfigs []*config.RelabelConfig
 	// Used for sending HTTP requests to the Alertmanager.
 	Do func(ctx context.Context, client *http.Client, req *http.Request) (*http.Response, error)
+
+	Registerer prometheus.Registerer
 }
 
 type alertMetrics struct {
@@ -147,7 +149,7 @@ func newAlertMetrics(r prometheus.Registerer, o *Options) *alertMetrics {
 }
 
 // New constructs a new Notifier.
-func New(o *Options, r prometheus.Registerer) *Notifier {
+func New(o *Options) *Notifier {
 	ctx, cancel := context.WithCancel(context.Background())
 
 	if o.Do == nil {
@@ -160,7 +162,7 @@ func New(o *Options, r prometheus.Registerer) *Notifier {
 		cancel:  cancel,
 		more:    make(chan struct{}, 1),
 		opts:    o,
-		metrics: newAlertMetrics(r, o),
+		metrics: newAlertMetrics(o.Registerer, o),
 	}
 }
 
diff --git a/notifier/notifier_test.go b/notifier/notifier_test.go
index 0a8b592507..9f479a02de 100644
--- a/notifier/notifier_test.go
+++ b/notifier/notifier_test.go
@@ -63,7 +63,7 @@ func TestPostPath(t *testing.T) {
 }
 
 func TestHandlerNextBatch(t *testing.T) {
-	h := New(&Options{}, prometheus.DefaultRegisterer)
+	h := New(&Options{})
 	defer unregisterMetrics()
 
 	for i := range make([]struct{}, 2*maxBatchSize+1) {
@@ -159,7 +159,7 @@ func TestHandlerSendAll(t *testing.T) {
 	defer server1.Close()
 	defer server2.Close()
 
-	h := New(&Options{}, prometheus.DefaultRegisterer)
+	h := New(&Options{})
 	defer unregisterMetrics()
 	h.alertmanagers = append(h.alertmanagers, &alertmanagerSet{
 		ams: []alertmanager{
@@ -227,7 +227,7 @@ func TestCustomDo(t *testing.T) {
 				Body: ioutil.NopCloser(nil),
 			}, nil
 		},
-	}, prometheus.DefaultRegisterer)
+	})
 	defer unregisterMetrics()
 
 	h.sendOne(context.Background(), nil, testURL, []byte(testBody))
@@ -250,7 +250,7 @@ func TestExternalLabels(t *testing.T) {
 				Replacement:  "c",
 			},
 		},
-	}, prometheus.DefaultRegisterer)
+	})
 	defer unregisterMetrics()
 
 	// This alert should get the external label attached.
@@ -305,7 +305,7 @@ func TestHandlerRelabel(t *testing.T) {
 				Replacement:  "renamed",
 			},
 		},
-	}, prometheus.DefaultRegisterer)
+	})
 	defer unregisterMetrics()
 
 	// This alert should be dropped due to the configuration
@@ -360,7 +360,7 @@ func TestHandlerQueueing(t *testing.T) {
 
 	h := New(&Options{
 		QueueCapacity: 3 * maxBatchSize,
-	}, prometheus.DefaultRegisterer)
+	})
 	defer unregisterMetrics()
 	h.alertmanagers = append(h.alertmanagers, &alertmanagerSet{
 		ams: []alertmanager{