diff --git a/cmd/prometheus/config.go b/cmd/prometheus/config.go
index e7ff539b4b..926df34e11 100644
--- a/cmd/prometheus/config.go
+++ b/cmd/prometheus/config.go
@@ -116,10 +116,6 @@ func init() {
 	)
 
 	// Alertmanager.
-	cfg.fs.Var(
-		&cfg.alertmanagerURLs, "alertmanager.url",
-		"Comma-separated list of Alertmanager URLs to send notifications to.",
-	)
 	cfg.fs.IntVar(
 		&cfg.notifier.QueueCapacity, "alertmanager.notification-queue-capacity", 10000,
 		"The capacity of the queue for pending alert manager notifications.",
diff --git a/cmd/prometheus/main.go b/cmd/prometheus/main.go
index 31be3abcac..a96ecbafcc 100644
--- a/cmd/prometheus/main.go
+++ b/cmd/prometheus/main.go
@@ -18,7 +18,6 @@ import (
 	"flag"
 	"fmt"
 	_ "net/http/pprof" // Comment this line to disable pprof endpoint.
-	"net/url"
 	"os"
 	"os/signal"
 	"syscall"
@@ -27,7 +26,6 @@ import (
 	"github.com/fabxc/tsdb"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/log"
-	"github.com/prometheus/common/model"
 	"github.com/prometheus/common/version"
 	"golang.org/x/net/context"
 
@@ -242,31 +240,6 @@ func reloadConfig(filename string, rls ...Reloadable) (err error) {
 		return fmt.Errorf("couldn't load configuration (-config.file=%s): %v", filename, err)
 	}
 
-	// Add AlertmanagerConfigs for legacy Alertmanager URL flags.
-	for us := range cfg.alertmanagerURLs {
-		u, err := url.Parse(us)
-		if err != nil {
-			return err
-		}
-		acfg := &config.AlertmanagerConfig{
-			Scheme:     u.Scheme,
-			PathPrefix: u.Path,
-			Timeout:    cfg.notifierTimeout,
-			ServiceDiscoveryConfig: config.ServiceDiscoveryConfig{
-				StaticConfigs: []*config.TargetGroup{
-					{
-						Targets: []model.LabelSet{
-							{
-								model.AddressLabel: model.LabelValue(u.Host),
-							},
-						},
-					},
-				},
-			},
-		}
-		conf.AlertingConfig.AlertmanagerConfigs = append(conf.AlertingConfig.AlertmanagerConfigs, acfg)
-	}
-
 	failed := false
 	for _, rl := range rls {
 		if err := rl.ApplyConfig(conf); err != nil {