diff --git a/app/scripts/lib/idStore.js b/app/scripts/lib/idStore.js
index 9846c84f0..9d0ca7f19 100644
--- a/app/scripts/lib/idStore.js
+++ b/app/scripts/lib/idStore.js
@@ -286,7 +286,7 @@ IdentityStore.prototype.addGasBuffer = function (gasHex) {
   var gas = new BN(gasHex, 16)
   var buffer = new BN('100000', 10)
   var result = gas.add(buffer)
-  return result.toString(16)
+  return ethUtil.addHexPrefix(result.toString(16))
 }
 
 // comes from metamask ui
diff --git a/test/unit/idStore-test.js b/test/unit/idStore-test.js
index 7f6324645..0a57d2121 100644
--- a/test/unit/idStore-test.js
+++ b/test/unit/idStore-test.js
@@ -154,5 +154,6 @@ describe('IdentityStore', function() {
     const bnResult = new BN(result, 16)
 
     assert.ok(bnResult.gt(gas), 'added more gas as buffer.')
+    assert.equal(result.indexOf('0x'), 0, 'include hex prefix')
   })
 })