diff --git a/app/scripts/lib/tx-state-manager.js b/app/scripts/lib/tx-state-manager.js
index 23c915a61..9e597ef37 100644
--- a/app/scripts/lib/tx-state-manager.js
+++ b/app/scripts/lib/tx-state-manager.js
@@ -140,8 +140,16 @@ module.exports = class TransactionStateManager extends EventEmitter {
   validateTxParams(txParams) {
     Object.keys(txParams).forEach((key) => {
       const value = txParams[key]
-      if (typeof value !== 'string') throw new Error(`${key}: ${value} in txParams is not a string`)
-      if (!ethUtil.isHexPrefixed(value)) throw new Error('is not hex prefixed, everything on txParams must be hex prefixed')
+      // validate types
+      switch (key) {
+        case 'chainId':
+          if (typeof value !== 'number') throw new Error(`${key} in txParams is not a Number. got: (${value})`)
+          break
+        default:
+          if (typeof value !== 'string') throw new Error(`${key} in txParams is not a string. got: (${value})`)
+          if (!ethUtil.isHexPrefixed(value)) throw new Error(`${key} in txParams is not hex prefixed. got: (${value})`)
+          break
+      }
     })
   }