diff --git a/etcdctl/command/util.go b/etcdctl/command/util.go
index 9b3452338..a8e6fa0a4 100644
--- a/etcdctl/command/util.go
+++ b/etcdctl/command/util.go
@@ -208,8 +208,19 @@ func mustNewClient(c *cli.Context) client.Client {
 			if err == client.ErrNoEndpoints {
 				fmt.Fprintf(os.Stderr, "etcd cluster has no published client endpoints.\n")
 				fmt.Fprintf(os.Stderr, "Try '--no-sync' if you want to access non-published client endpoints(%s).\n", strings.Join(hc.Endpoints(), ","))
+				handleError(ExitServerError, err)
+			}
+
+			// fail-back to try sync cluster with peer API. this is for making etcdctl work with etcd 0.4.x.
+			// TODO: remove this when we deprecate the support for etcd 0.4.
+			eps, serr := syncWithPeerAPI(c, ctx, hc.Endpoints())
+			if serr != nil {
+				handleError(ExitServerError, serr)
+			}
+			err = hc.SetEndpoints(eps)
+			if err != nil {
+				handleError(ExitServerError, err)
 			}
-			handleError(ExitServerError, err)
 		}
 		if debug {
 			fmt.Fprintf(os.Stderr, "got endpoints(%s) after sync\n", strings.Join(hc.Endpoints(), ","))
@@ -271,3 +282,44 @@ func newClient(c *cli.Context) (client.Client, error) {
 func contextWithTotalTimeout(c *cli.Context) (context.Context, context.CancelFunc) {
 	return context.WithTimeout(context.Background(), c.GlobalDuration("total-timeout"))
 }
+
+// syncWithPeerAPI syncs cluster with peer API defined at
+// https://github.com/coreos/etcd/blob/v0.4.9/server/server.go#L311.
+// This exists for backward compatibility with etcd 0.4.x.
+func syncWithPeerAPI(c *cli.Context, ctx context.Context, knownPeers []string) ([]string, error) {
+	tr, err := getTransport(c)
+	if err != nil {
+		return nil, err
+	}
+
+	var (
+		body []byte
+		resp *http.Response
+	)
+	for _, p := range knownPeers {
+		var req *http.Request
+		req, err = http.NewRequest("GET", p+"/v2/peers", nil)
+		if err != nil {
+			continue
+		}
+		resp, err = tr.RoundTrip(req)
+		if err != nil {
+			continue
+		}
+		if resp.StatusCode != http.StatusOK {
+			resp.Body.Close()
+			continue
+		}
+		body, err = ioutil.ReadAll(resp.Body)
+		resp.Body.Close()
+		if err != nil {
+			continue
+		}
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	// Parse the peers API format: https://github.com/coreos/etcd/blob/v0.4.9/server/server.go#L311
+	return strings.Split(string(body), ", "), nil
+}