diff --git a/main.go b/main.go
index 17c32bedc..f39f148ea 100644
--- a/main.go
+++ b/main.go
@@ -45,7 +45,7 @@ var (
 	configFile         = flag.String("configFile", "prometheus.conf", "Prometheus configuration file name.")
 	metricsStoragePath = flag.String("metricsStoragePath", "/tmp/metrics", "Base path for metrics storage.")
 
-	alertmanagerUrl = flag.String("alertmanager.url", "", "The URL of the alert manager to send notifications to.")
+	alertmanagerURL = flag.String("alertmanager.url", "", "The URL of the alert manager to send notifications to.")
 
 	remoteTSDBUrl     = flag.String("storage.remote.url", "", "The URL of the OpenTSDB instance to send samples to.")
 	remoteTSDBTimeout = flag.Duration("storage.remote.timeout", 30*time.Second, "The timeout to use when sending samples to OpenTSDB.")
@@ -67,6 +67,20 @@ var (
 	printVersion = flag.Bool("version", false, "print version information")
 )
 
+// Instrumentation.
+var (
+	samplesQueueCapDesc = registry.NewDesc(
+		"prometheus_samples_queue_capacity",
+		"Capacity of the queue for unwritten samples.",
+		nil, nil,
+	)
+	samplesQueueLenDesc = registry.NewDesc(
+		"prometheus_samples_queue_length",
+		"Current number of items in the queue for unwritten samples. Each item comprises all samples exposed by one target as one metric family (i.e. metrics of the same name).",
+		nil, nil,
+	)
+)
+
 type prometheus struct {
 	unwrittenSamples chan *extraction.Result
 
@@ -99,8 +113,7 @@ func NewPrometheus() *prometheus {
 	targetManager := retrieval.NewTargetManager(ingester)
 	targetManager.AddTargetsFromConfig(conf)
 
-	notificationHandler := notification.NewNotificationHandler(*alertmanagerUrl, *notificationQueueCapacity)
-	registry.MustRegister(notificationHandler)
+	notificationHandler := notification.NewNotificationHandler(*alertmanagerURL, *notificationQueueCapacity)
 
 	o := &local.MemorySeriesStorageOptions{
 		MemoryEvictionInterval:     *memoryEvictionInterval,
@@ -115,7 +128,6 @@ func NewPrometheus() *prometheus {
 	if err != nil {
 		glog.Fatal("Error opening memory series storage: ", err)
 	}
-	registry.MustRegister(memStorage)
 
 	ruleManager := manager.NewRuleManager(&manager.RuleManagerOptions{
 		Results:             unwrittenSamples,
@@ -134,7 +146,6 @@ func NewPrometheus() *prometheus {
 	} else {
 		openTSDB := opentsdb.NewClient(*remoteTSDBUrl, *remoteTSDBTimeout)
 		remoteTSDBQueue = remote.NewTSDBQueueManager(openTSDB, 512)
-		registry.MustRegister(remoteTSDBQueue)
 	}
 
 	flags := map[string]string{}
@@ -259,6 +270,36 @@ func (p *prometheus) close() {
 	// remaining shut-downs happen in Serve().
 }
 
+// Describe implements registry.Collector.
+func (p *prometheus) Describe(ch chan<- *registry.Desc) {
+	ch <- samplesQueueCapDesc
+	ch <- samplesQueueLenDesc
+	p.notificationHandler.Describe(ch)
+	p.storage.Describe(ch)
+	if p.remoteTSDBQueue != nil {
+		p.remoteTSDBQueue.Describe(ch)
+	}
+}
+
+// Collect implements registry.Collector.
+func (p *prometheus) Collect(ch chan<- registry.Metric) {
+	ch <- registry.MustNewConstMetric(
+		samplesQueueCapDesc,
+		registry.GaugeValue,
+		float64(cap(p.unwrittenSamples)),
+	)
+	ch <- registry.MustNewConstMetric(
+		samplesQueueLenDesc,
+		registry.GaugeValue,
+		float64(len(p.unwrittenSamples)),
+	)
+	p.notificationHandler.Collect(ch)
+	p.storage.Collect(ch)
+	if p.remoteTSDBQueue != nil {
+		p.remoteTSDBQueue.Collect(ch)
+	}
+}
+
 func main() {
 	flag.Parse()
 	versionInfoTmpl.Execute(os.Stdout, BuildInfo)
@@ -267,5 +308,7 @@ func main() {
 		os.Exit(0)
 	}
 
-	NewPrometheus().Serve()
+	p := NewPrometheus()
+	registry.MustRegister(p)
+	p.Serve()
 }