diff --git a/k8s/blockchain.go b/k8s/blockchain.go
index f3a6b879..e2145b6d 100644
--- a/k8s/blockchain.go
+++ b/k8s/blockchain.go
@@ -17,21 +17,36 @@
 package k8s
 
 import (
+	"crypto/ecdsa"
 	"errors"
 	"fmt"
 	"time"
 
+	"github.com/ethereum/go-ethereum/common"
+
 	"github.com/getamis/istanbul-tools/charts"
 	istcommon "github.com/getamis/istanbul-tools/common"
 	"github.com/getamis/istanbul-tools/container"
 )
 
-func NewBlockchain(numOfValidators int, gaslimit uint64, options ...Option) (bc *blockchain) {
+func NewBlockchain(numOfValidators int, numOfExtraAccounts int, gaslimit uint64, options ...Option) (bc *blockchain) {
 	_, nodekeys, addrs := istcommon.GenerateKeys(numOfValidators)
 	ips := istcommon.GenerateIPs(len(nodekeys))
 
+	extraKeys := make([][]*ecdsa.PrivateKey, numOfValidators)
+	extraAddrs := make([][]common.Address, numOfValidators)
+
+	allAddrs := addrs
+
+	if numOfExtraAccounts > 0 {
+		for i := 0; i < numOfValidators; i++ {
+			extraKeys[i], _, extraAddrs[i] = istcommon.GenerateKeys(numOfExtraAccounts)
+			allAddrs = append(allAddrs, extraAddrs[i]...)
+		}
+	}
+
 	bc = &blockchain{
-		genesis:     charts.NewGenesisChart(addrs, uint64(gaslimit)),
+		genesis:     charts.NewGenesisChart(allAddrs, uint64(gaslimit)),
 		staticNodes: charts.NewStaticNodesChart(nodekeys, ips),
 	}
 
@@ -44,7 +59,7 @@ func NewBlockchain(numOfValidators int, gaslimit uint64, options ...Option) (bc
 		bc.genesis.Uninstall()
 		return nil
 	}
-	bc.setupValidators(numOfValidators, nodekeys, ips, options...)
+	bc.setupValidators(numOfValidators, extraKeys, nodekeys, ips, options...)
 	return bc
 }
 
@@ -104,7 +119,7 @@ func (bc *blockchain) Validators() []container.Ethereum {
 
 // ----------------------------------------------------------------------------
 
-func (bc *blockchain) setupValidators(num int, nodekeys []string, ips []string, options ...Option) {
+func (bc *blockchain) setupValidators(num int, extraKeys [][]*ecdsa.PrivateKey, nodekeys []string, ips []string, options ...Option) {
 	for i := 0; i < num; i++ {
 		var opts []Option
 		opts = append(opts, options...)
@@ -112,6 +127,7 @@ func (bc *blockchain) setupValidators(num int, nodekeys []string, ips []string,
 		opts = append(opts, Name(fmt.Sprintf("%d", i)))
 		opts = append(opts, NodeKeyHex(nodekeys[i]))
 		opts = append(opts, IPAddress(ips[i]))
+		opts = append(opts, ExtraAccounts(extraKeys[i]))
 
 		geth := NewEthereum(
 			opts...,
diff --git a/k8s/blockchain_example.go b/k8s/blockchain_example.go
index 2ca175c1..47be6c3b 100644
--- a/k8s/blockchain_example.go
+++ b/k8s/blockchain_example.go
@@ -23,6 +23,7 @@ import (
 func ExampleK8SBlockchain() {
 	chain := NewBlockchain(
 		4,
+		0,
 		21000*1000,
 		ImageRepository("quay.io/amis/geth"),
 		ImageTag("istanbul_develop"),
diff --git a/k8s/option.go b/k8s/option.go
index 96c0732f..d1c755a2 100644
--- a/k8s/option.go
+++ b/k8s/option.go
@@ -16,7 +16,10 @@
 
 package k8s
 
-import "fmt"
+import (
+	"crypto/ecdsa"
+	"fmt"
+)
 
 type Option func(*ethereum)
 
@@ -86,3 +89,9 @@ func Verbosity(verbosity int) Option {
 		eth.args = append(eth.args, fmt.Sprintf("ethereum.verbosity=%d", verbosity))
 	}
 }
+
+func ExtraAccounts(keys []*ecdsa.PrivateKey) Option {
+	return func(eth *ethereum) {
+		eth.accounts = keys
+	}
+}