diff --git a/5-redux-react/src/js/components/Layout.js b/5-redux-react/src/js/components/Layout.js
index 41517fb3..8d416cd7 100644
--- a/5-redux-react/src/js/components/Layout.js
+++ b/5-redux-react/src/js/components/Layout.js
@@ -27,7 +27,7 @@ export default class Layout extends React.Component {
       return <button onClick={this.fetchTweets.bind(this)}>load tweets</button>
     }
 
-    const mappedTweets = tweets.map(tweet => <li>{tweet.text}</li>)
+    const mappedTweets = tweets.map(tweet => <li key={tweet.id}>{tweet.text}</li>)
 
     return <div>
       <h1>{user.name}</h1>