diff --git a/src/hdwallet.js b/src/hdwallet.js
index 00a02c0..f40582f 100644
--- a/src/hdwallet.js
+++ b/src/hdwallet.js
@@ -13,7 +13,8 @@ var HDWallet = module.exports = function(seed, network) {
 
     var I = Crypto.HMAC(Crypto.SHA512, seed, 'Bitcoin seed', { asBytes: true })
     this.chaincode = I.slice(32)
-    this.priv = new ECKey(I.slice(0, 32).concat([1]), true)
+    this.keyVersion = network == 'Bitcoin' ? Address.address_types.prod : Address.address_types.testnet
+    this.priv = new ECKey(I.slice(0, 32).concat([1]), true, this.keyVersion)
     this.pub = this.priv.getPub()
     this.network = network || 'Bitcoin'
     this.index = 0
@@ -106,10 +107,10 @@ HDWallet.fromBytes = function(input) {
     // 33 bytes: the public key or private key data (0x02 + X or 0x03 + X for
     // public keys, 0x00 + k for private keys)
     if (type == 'private') {
-        hd.priv = new ECKey(input.slice(46, 78).concat([1]), true)
+        hd.priv = new ECKey(input.slice(46, 78).concat([1]), true, this.keyVersion)
         hd.pub = hd.priv.getPub()
     } else {
-        hd.pub = new ECPubKey(input.slice(45, 78), true)
+        hd.pub = new ECPubKey(input.slice(45, 78), true, this.keyVersion)
     }
 
     return hd
@@ -213,10 +214,11 @@ HDWallet.prototype.derive = function(i) {
         // ki = IL + kpar (mod n).
         hd.priv = this.priv.add(new ECKey(IL.concat([1])))
         hd.priv.compressed = true
+        hd.priv.version = this.keyVersion
         hd.pub = hd.priv.getPub()
     } else {
         // Ki = (IL + kpar)*G = IL*G + Kpar
-        hd.pub = this.pub.add(new ECKey(IL.concat([1])).getPub())
+        hd.pub = this.pub.add(new ECKey(IL.concat([1]), true, this.keyVersion).getPub())
     }
 
     // ci = IR.
diff --git a/test/wallet.js b/test/wallet.js
index 0f39d02..44f6164 100644
--- a/test/wallet.js
+++ b/test/wallet.js
@@ -1,4 +1,5 @@
 var Wallet = require('../src/wallet.js')
+var Address = require('../src/address.js')
 var assert = require('assert')
 
 describe('Wallet', function() {
@@ -33,4 +34,20 @@ describe('Wallet', function() {
       assert.equal(wallet.derivationMethod, 'public')
     })
   })
+
+  describe('networkType', function() {
+    it('ensures that a mainnet Wallet has mainnet child keys (pub and priv)', function() {
+        var w = Wallet("foobar", {network: "Bitcoin"})
+        assert(w.getMasterKey().priv.version == Address.address_types['prod'])
+        w.generateAddress()
+        assert(w.getPrivateKey(0).priv.version == Address.address_types['prod'])
+    })
+
+    it('ensures that a testnet Wallet has testnet child keys (pub and priv)', function() {
+        var w = Wallet("foobar", {network: "BitcoinTest"})
+        assert(w.getMasterKey().priv.version == Address.address_types['testnet'])
+        w.generateAddress()
+        assert(w.getPrivateKey(0).priv.version == Address.address_types['testnet'])
+    })
+  })
 })