diff --git a/src/app/tabs/run-tab.js b/src/app/tabs/run-tab.js
index 5fff59d730..01be4b6eb7 100644
--- a/src/app/tabs/run-tab.js
+++ b/src/app/tabs/run-tab.js
@@ -12,6 +12,7 @@ var copyToClipboard = require('../ui/copy-to-clipboard')
 var Recorder = require('../../recorder')
 var EventManager = remixLib.EventManager
 var addTooltip = require('../ui/tooltip')
+var ethJSUtil = require('ethereumjs-util')
 
 var csjs = require('csjs-inject')
 var css = require('./styles/run-tab-styles')
@@ -311,6 +312,12 @@ function contractDropdown (events, appAPI, appEvents, instanceContainer) {
     noInstancesText.style.display = 'none'
     var contractNames = document.querySelector(`.${css.contractNames.classNames[0]}`)
     var address = atAddressButtonInput.value
+    if (!ethJSUtil.isValidAddress(address)) {
+      return modalDialogCustom.alert('Invalid address.')
+    }
+    if (/[a-f]/.test(address) && /[A-F]/.test(address) && !ethJSUtil.isValidChecksumAddress(address)) {
+      return modalDialogCustom.alert('Invalid checksum address.')
+    }
     if (/.(.abi)$/.exec(appAPI.currentFile())) {
       modalDialogCustom.confirm(null, 'Do you really want to interact with ' + address + ' using the current ABI definition ?', () => {
         var abi
diff --git a/test-browser/helpers/contracts.js b/test-browser/helpers/contracts.js
index 6d01addfa9..183612edcf 100644
--- a/test-browser/helpers/contracts.js
+++ b/test-browser/helpers/contracts.js
@@ -1,5 +1,6 @@
 'use strict'
 var deepequal = require('deep-equal')
+var ethJSUtil = require('ethereumjs-util')
 
 module.exports = {
   getCompiledContracts: getCompiledContracts,
@@ -161,11 +162,16 @@ function setEditorValue (value, callback) {
   return this
 }
 
-function addInstance (browser, address, callback) {
+function addInstance(browser, address, isValidFormat, isValidChecksum, callback) {
   browser.setValue('.ataddressinput', address, function () {
     browser.click('div[class^="atAddress"]')
       .perform((client, done) => {
         browser.execute(function () {
+          if (!isValidFormat) {
+            browser.assert.fail(document.querySelector('div[class^="modalBody"] div').innerHTML, 'Invalid address.', '')
+          } else if (!isValidChecksum) {
+            browser.assert.fail(document.querySelector('div[class^="modalBody"] div').innerHTML, 'Invalid checksum address.', '')
+          }
           document.querySelector('#modal-footer-ok').click()
         }, [], function (result) {
           done()
diff --git a/test-browser/tests/ballot.js b/test-browser/tests/ballot.js
index ecc846fe62..00dabb091a 100644
--- a/test-browser/tests/ballot.js
+++ b/test-browser/tests/ballot.js
@@ -72,8 +72,14 @@ function runTests (browser, testData) {
         })
       })
       .perform((client, done) => {
-        console.log('addInstance 0x692a70d2e424a56d2c6c27aa97d1a86395877b3a')
-        contractHelper.addInstance(browser, '0x692a70d2e424a56d2c6c27aa97d1a86395877b3a', () => {
+        console.log('addInstance invalid checksum address 0x692a70d2e424a56d2c6c27aa97d1a86395877b3a')
+        contractHelper.addInstance(browser, '0x692a70d2e424a56d2c6c27aa97d1a86395877b3a', true, false, () => {
+          done()
+        })
+      })
+      .perform((client, done) => {
+        console.log('addInstance 0x692a70D2e424a56D2C6C27aA97D1a86395877b3A')
+        contractHelper.addInstance(browser, '0x692a70D2e424a56D2C6C27aA97D1a86395877b3A', true, true, () => {
           done()
         })
       })