diff --git a/src/server.go b/src/server.go
index 80e7e31..88e7c28 100644
--- a/src/server.go
+++ b/src/server.go
@@ -195,7 +195,7 @@ func (a *App) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	}
 
 	// lock the key while a PUT or DELETE is in progress
-	if r.Method == "POST" || r.Method == "PUT" || r.Method == "DELETE" || r.Method == "UNLINK" || r.Method == "REBALANCE" {
+	if r.Method == "POST" || r.Method == "PUT" || r.Method == "REPLACE" || r.Method == "DELETE" || r.Method == "UNLINK" || r.Method == "REBALANCE" {
 		if !a.LockKey(lkey) {
 			// Conflict, retry later
 			w.WriteHeader(409)
@@ -324,19 +324,21 @@ func (a *App) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 			w.Write([]byte("<CompleteMultipartUploadResult></CompleteMultipartUploadResult>"))
 			return
 		}
-	case "PUT":
+	case "PUT", "REPLACE":
 		// no empty values
 		if r.ContentLength == 0 {
 			w.WriteHeader(411)
 			return
 		}
 
-		// check if we already have the key, and it's not deleted
-		rec := a.GetRecord(key)
-		if rec.deleted == NO {
-			// Forbidden to overwrite with PUT
-			w.WriteHeader(403)
-			return
+		if r.Method == "PUT" {
+			// check if we already have the key, and it's not deleted
+			rec := a.GetRecord(key)
+			if rec.deleted == NO {
+				// Forbidden to overwrite with PUT
+				w.WriteHeader(403)
+				return
+			}
 		}
 
 		if pn := r.URL.Query().Get("partNumber"); pn != "" {
diff --git a/tools/test.py b/tools/test.py
index f3ebf66..09e4e89 100755
--- a/tools/test.py
+++ b/tools/test.py
@@ -124,6 +124,42 @@ def test_head_request(self):
     # redirect, content length should be size of data
     self.assertEqual(int(r.headers['content-length']), len(data))
 
+  def test_put_replace(self):
+    key = self.get_fresh_key()
+
+    r = requests.put(key, data="abc")
+    self.assertEqual(r.status_code, 201)
+
+    r = requests.request("REPLACE", key, data="123")
+    self.assertEqual(r.status_code, 201)
+
+    r = requests.get(key)
+    self.assertEqual(r.status_code, 200)
+    self.assertEqual(r.text, "123")
+
+    r = requests.delete(key)
+    self.assertEqual(r.status_code, 204)
+
+  def test_replace_replace(self):
+    key = self.get_fresh_key()
+
+    r = requests.request("REPLACE", key, data="123")
+    self.assertEqual(r.status_code, 201)
+
+    r = requests.get(key)
+    self.assertEqual(r.status_code, 200)
+    self.assertEqual(r.text, "123")
+
+    r = requests.request("REPLACE", key, data="456")
+    self.assertEqual(r.status_code, 201)
+
+    r = requests.get(key)
+    self.assertEqual(r.status_code, 200)
+    self.assertEqual(r.text, "456")
+
+    r = requests.delete(key)
+    self.assertEqual(r.status_code, 204)
+
   def test_large_key(self):
     key = self.get_fresh_key()
 
diff --git a/tools/thrasher.go b/tools/thrasher.go
index 4487cdb..6e696ec 100644
--- a/tools/thrasher.go
+++ b/tools/thrasher.go
@@ -29,8 +29,8 @@ func remote_delete(remote string) error {
 	return nil
 }
 
-func remote_put(remote string, length int64, body io.Reader) error {
-	req, err := http.NewRequest("PUT", remote, body)
+func remote_set(method string, remote string, length int64, body io.Reader) error {
+	req, err := http.NewRequest(method, remote, body)
 	if err != nil {
 		return err
 	}
@@ -41,7 +41,7 @@ func remote_put(remote string, length int64, body io.Reader) error {
 	}
 	defer resp.Body.Close()
 	if resp.StatusCode != 201 && resp.StatusCode != 204 {
-		return fmt.Errorf("remote_put: wrong status code %d", resp.StatusCode)
+		return fmt.Errorf("remote_set: wrong status code %d", resp.StatusCode)
 	}
 	return nil
 }
@@ -76,9 +76,14 @@ func main() {
 		go func() {
 			for {
 				key := <-reqs
-				value := fmt.Sprintf("value-%d", rand.Int())
-				if err := remote_put("http://localhost:3000/"+key, int64(len(value)), strings.NewReader(value)); err != nil {
-					fmt.Println("PUT FAILED", err)
+				val := rand.Int()
+				value := fmt.Sprintf("value-%d", val)
+				method := "PUT"
+				if val % 4 == 0 {
+					method = "REPLACE"
+				}
+				if err := remote_set(method, "http://localhost:3000/"+key, int64(len(value)), strings.NewReader(value)); err != nil {
+					fmt.Println(method + " FAILED", err)
 					resp <- false
 					continue
 				}