diff --git a/lib/blockchain.js b/lib/blockchain.js
index adf0f871..cb67b2d1 100644
--- a/lib/blockchain.js
+++ b/lib/blockchain.js
@@ -27,7 +27,7 @@ Blockchain.prototype.generate_basic_command = function() {
   cmd += "--networkid " + config.networkId + " ";
   cmd += "--rpccorsdomain \"" + config.rpcWhitelist + "\" ";
 
-  if(config.testnet !== void 0){
+  if(config.testnet){
     cmd += "--testnet "
   }
 
diff --git a/lib/config/blockchain.js b/lib/config/blockchain.js
index 99f861c3..bb93342a 100644
--- a/lib/config/blockchain.js
+++ b/lib/config/blockchain.js
@@ -51,7 +51,8 @@ BlockchainConfig.prototype.config = function(env) {
     mine_when_needed: config.mine_when_needed || false,
     whisper: config.whisper || false,
     account: config.account,
-    geth_extra_opts: config.geth_extra_opts
+    geth_extra_opts: config.geth_extra_opts,
+    testnet: config.testnet || false
   }
 
   return config;