diff --git a/tools/benchmark/cmd/stm.go b/tools/benchmark/cmd/stm.go
new file mode 100644
index 000000000..99ac41d2d
--- /dev/null
+++ b/tools/benchmark/cmd/stm.go
@@ -0,0 +1,153 @@
+// Copyright 2016 CoreOS, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cmd
+
+import (
+	"encoding/binary"
+	"fmt"
+	"math/rand"
+	"os"
+	"time"
+
+	"github.com/coreos/etcd/Godeps/_workspace/src/github.com/cheggaaa/pb"
+	"github.com/coreos/etcd/Godeps/_workspace/src/github.com/spf13/cobra"
+	"github.com/coreos/etcd/Godeps/_workspace/src/golang.org/x/net/context"
+	v3 "github.com/coreos/etcd/clientv3"
+	v3sync "github.com/coreos/etcd/clientv3/concurrency"
+)
+
+// stmCmd represents the STM benchmark command
+var stmCmd = &cobra.Command{
+	Use:   "stm",
+	Short: "Benchmark STM",
+
+	Run: stmFunc,
+}
+
+type stmApply func(v3sync.STM) error
+
+var (
+	stmIsolation    string
+	stmTotal        int
+	stmKeysPerTxn   int
+	stmKeyCount     int
+	stmValSize      int
+	stmWritePercent int
+	mkSTM           func(context.Context, *v3.Client, func(v3sync.STM) error) (*v3.TxnResponse, error)
+)
+
+func init() {
+	RootCmd.AddCommand(stmCmd)
+
+	stmCmd.Flags().StringVar(&stmIsolation, "isolation", "r", "Repeatable Reads (r) or Serializable (s)")
+	stmCmd.Flags().IntVar(&stmKeyCount, "keys", 1, "Total unique keys accessible by the benchmark")
+	stmCmd.Flags().IntVar(&stmTotal, "total", 10000, "Total number of completed STM transactions")
+	stmCmd.Flags().IntVar(&stmKeysPerTxn, "keys-per-txn", 1, "Number of keys to access per transaction")
+	stmCmd.Flags().IntVar(&stmWritePercent, "txn-wr-percent", 50, "Percentage of keys to overwrite per transaction")
+	stmCmd.Flags().IntVar(&stmValSize, "val-size", 8, "Value size of each STM put request")
+}
+
+func stmFunc(cmd *cobra.Command, args []string) {
+	if stmKeyCount <= 0 {
+		fmt.Fprintf(os.Stderr, "expected positive --keys, got (%v)", stmKeyCount)
+		os.Exit(1)
+	}
+
+	if stmWritePercent < 0 || stmWritePercent > 100 {
+		fmt.Fprintf(os.Stderr, "expected [0, 100] --txn-wr-percent, got (%v)", stmWritePercent)
+		os.Exit(1)
+	}
+
+	if stmKeysPerTxn < 0 || stmKeysPerTxn > stmKeyCount {
+		fmt.Fprintf(os.Stderr, "expected --keys-per-txn between 0 and %v, got (%v)", stmKeyCount, stmKeysPerTxn)
+		os.Exit(1)
+	}
+
+	switch stmIsolation {
+	case "r":
+		mkSTM = v3sync.NewSTMRepeatable
+	case "l":
+		mkSTM = v3sync.NewSTMSerializable
+	default:
+		fmt.Fprintln(os.Stderr, cmd.Usage())
+		os.Exit(1)
+	}
+
+	results = make(chan result)
+	requests := make(chan stmApply, totalClients)
+	bar = pb.New(stmTotal)
+
+	clients := mustCreateClients(totalClients, totalConns)
+
+	bar.Format("Bom !")
+	bar.Start()
+
+	for i := range clients {
+		wg.Add(1)
+		go doSTM(context.Background(), clients[i], requests)
+	}
+
+	pdoneC := printReport(results)
+
+	go func() {
+		for i := 0; i < stmTotal; i++ {
+			kset := make(map[string]struct{})
+			for len(kset) != stmKeysPerTxn {
+				k := make([]byte, 16)
+				binary.PutVarint(k, int64(rand.Intn(stmKeyCount)))
+				s := string(k)
+				kset[s] = struct{}{}
+			}
+
+			applyf := func(s v3sync.STM) error {
+				wrs := int(float32(len(kset)*stmWritePercent) / 100.0)
+				for k := range kset {
+					s.Get(k)
+					if wrs > 0 {
+						s.Put(k, string(mustRandBytes(stmValSize)))
+						wrs--
+					}
+				}
+				return nil
+			}
+
+			requests <- applyf
+		}
+		close(requests)
+	}()
+
+	wg.Wait()
+
+	bar.Finish()
+
+	close(results)
+	<-pdoneC
+}
+
+func doSTM(ctx context.Context, client *v3.Client, requests <-chan stmApply) {
+	defer wg.Done()
+
+	for applyf := range requests {
+		st := time.Now()
+		_, err := v3sync.NewSTMRepeatable(context.TODO(), client, applyf)
+
+		var errStr string
+		if err != nil {
+			errStr = err.Error()
+		}
+		results <- result{errStr: errStr, duration: time.Since(st), happened: time.Now()}
+		bar.Increment()
+	}
+}