diff --git a/common/resolver/resolver.go b/common/resolver/resolver.go
index 1e6d03ffb..42348a89c 100644
--- a/common/resolver/resolver.go
+++ b/common/resolver/resolver.go
@@ -24,11 +24,11 @@ var HashRegContractAddress string = "0000000000000000000000000000000000000000000
 
 func CreateContracts(xeth *xe.XEth, addr string) {
 	var err error
-	URLHintContractAddress, err = xeth.Transact(addr, "", "100000000000", "1000000", "100000", ContractCodeURLhint)
+	URLHintContractAddress, err = xeth.Transact(addr, "", "", "100000000000", "1000000", "100000", ContractCodeURLhint)
 	if err != nil {
 		panic(err)
 	}
-	HashRegContractAddress, err = xeth.Transact(addr, "", "100000000000", "1000000", "100000", ContractCodeHashReg)
+	HashRegContractAddress, err = xeth.Transact(addr, "", "", "100000000000", "1000000", "100000", ContractCodeHashReg)
 	if err != nil {
 		panic(err)
 	}
diff --git a/rpc/api.go b/rpc/api.go
index 6d3a20bfa..b79a1306e 100644
--- a/rpc/api.go
+++ b/rpc/api.go
@@ -173,7 +173,13 @@ func (api *EthereumApi) GetRequestReply(req *RpcRequest, reply *interface{}) err
 			return fmt.Errorf("Transaction not confirmed")
 		}
 
-		v, err := api.xeth().Transact(args.From, args.To, args.Value.String(), args.Gas.String(), args.GasPrice.String(), args.Data)
+		// nonce may be nil ("guess" mode)
+		var nonce string
+		if args.Nonce != nil {
+			nonce = args.Nonce.String()
+		}
+
+		v, err := api.xeth().Transact(args.From, args.To, nonce, args.Value.String(), args.Gas.String(), args.GasPrice.String(), args.Data)
 		if err != nil {
 			return err
 		}
diff --git a/rpc/args.go b/rpc/args.go
index 4bd48e6d6..e61f28c4f 100644
--- a/rpc/args.go
+++ b/rpc/args.go
@@ -157,6 +157,7 @@ func (args *GetBlockByNumberArgs) UnmarshalJSON(b []byte) (err error) {
 type NewTxArgs struct {
 	From     string
 	To       string
+	Nonce    *big.Int
 	Value    *big.Int
 	Gas      *big.Int
 	GasPrice *big.Int
@@ -170,6 +171,7 @@ func (args *NewTxArgs) UnmarshalJSON(b []byte) (err error) {
 	var ext struct {
 		From     string
 		To       string
+		Nonce    interface{}
 		Value    interface{}
 		Gas      interface{}
 		GasPrice interface{}
@@ -200,6 +202,14 @@ func (args *NewTxArgs) UnmarshalJSON(b []byte) (err error) {
 	args.Data = ext.Data
 
 	var num *big.Int
+	if ext.Nonce != nil {
+		num, err = numString(ext.Nonce)
+		if err != nil {
+			return err
+		}
+	}
+	args.Nonce = num
+
 	if ext.Value == nil {
 		num = big.NewInt(0)
 	} else {
diff --git a/xeth/xeth.go b/xeth/xeth.go
index 692fb338c..ac59069d5 100644
--- a/xeth/xeth.go
+++ b/xeth/xeth.go
@@ -648,7 +648,7 @@ func (self *XEth) ConfirmTransaction(tx string) bool {
 
 }
 
-func (self *XEth) Transact(fromStr, toStr, valueStr, gasStr, gasPriceStr, codeStr string) (string, error) {
+func (self *XEth) Transact(fromStr, toStr, nonceStr, valueStr, gasStr, gasPriceStr, codeStr string) (string, error) {
 	var (
 		from             = common.HexToAddress(fromStr)
 		to               = common.HexToAddress(toStr)
@@ -704,7 +704,13 @@ func (self *XEth) Transact(fromStr, toStr, valueStr, gasStr, gasPriceStr, codeSt
 	}
 
 	state := self.backend.ChainManager().TxState()
-	nonce := state.NewNonce(from)
+
+	var nonce uint64
+	if len(nonceStr) != 0 {
+		nonce = common.Big(nonceStr).Uint64()
+	} else {
+		nonce = state.NewNonce(from)
+	}
 	tx.SetNonce(nonce)
 
 	if err := self.sign(tx, from, false); err != nil {