diff --git a/Examples/UIExplorer/ActionSheetIOSExample.js b/Examples/UIExplorer/ActionSheetIOSExample.js
index 9b164de14..1ee487ed5 100644
--- a/Examples/UIExplorer/ActionSheetIOSExample.js
+++ b/Examples/UIExplorer/ActionSheetIOSExample.js
@@ -1,6 +1,7 @@
 /**
-*  * Copyright 2004-present Facebook. All Rights Reserved.
-*   */
+ * Copyright 2004-present Facebook. All Rights Reserved.
+ * @flow
+ */
 'use strict';
 
 var React = require('react-native');
@@ -103,10 +104,10 @@ exports.description = 'Interface to show iOS\' action sheets';
 exports.examples = [
   {
     title: 'Show Action Sheet',
-    render() { return <ActionSheetExample />; }
+    render(): ReactElement { return <ActionSheetExample />; }
   },
   {
     title: 'Show Share Action Sheet',
-    render() { return <ShareActionSheetExample />; }
+    render(): ReactElement { return <ShareActionSheetExample />; }
   }
 ];
diff --git a/Examples/UIExplorer/ActivityIndicatorExample.js b/Examples/UIExplorer/ActivityIndicatorExample.js
index 3371551a0..60f69843c 100644
--- a/Examples/UIExplorer/ActivityIndicatorExample.js
+++ b/Examples/UIExplorer/ActivityIndicatorExample.js
@@ -1,5 +1,6 @@
 /**
  * Copyright 2004-present Facebook. All Rights Reserved.
+ * @flow
  */
 'use strict';
 
@@ -128,7 +129,7 @@ exports.examples = [
   },
   {
     title: 'Start/stop',
-    render: function() {
+    render: function(): ReactElement {
       return <ToggleAnimatingActivityIndicator />;
     }
   },
diff --git a/Examples/UIExplorer/AdSupportIOSExample.js b/Examples/UIExplorer/AdSupportIOSExample.js
index a3d720f01..4047dd43a 100644
--- a/Examples/UIExplorer/AdSupportIOSExample.js
+++ b/Examples/UIExplorer/AdSupportIOSExample.js
@@ -1,5 +1,6 @@
 /**
  * Copyright 2004-present Facebook. All Rights Reserved.
+ * @flow
  */
 'use strict';
 
@@ -19,7 +20,7 @@ exports.description = 'Example of using the ad support API.';
 exports.examples = [
   {
     title: 'Ad Support IOS',
-    render: function() {
+    render: function(): ReactElement {
       return <AdSupportIOSExample />;
     },
   }
diff --git a/Examples/UIExplorer/AlertIOSExample.js b/Examples/UIExplorer/AlertIOSExample.js
index a2b92d975..6897007fc 100644
--- a/Examples/UIExplorer/AlertIOSExample.js
+++ b/Examples/UIExplorer/AlertIOSExample.js
@@ -1,5 +1,6 @@
 /**
  * Copyright 2004-present Facebook. All Rights Reserved.
+ * @flow
  */
 'use strict';
 
diff --git a/Examples/UIExplorer/AppStateExample.js b/Examples/UIExplorer/AppStateExample.js
index ea6400b91..9e93a57fc 100644
--- a/Examples/UIExplorer/AppStateExample.js
+++ b/Examples/UIExplorer/AppStateExample.js
@@ -1,5 +1,6 @@
 /**
  * Copyright 2004-present Facebook. All Rights Reserved.
+ * @flow
  */
 'use strict';
 
diff --git a/Examples/UIExplorer/AppStateIOSExample.js b/Examples/UIExplorer/AppStateIOSExample.js
index 845b2e049..e28857fc8 100644
--- a/Examples/UIExplorer/AppStateIOSExample.js
+++ b/Examples/UIExplorer/AppStateIOSExample.js
@@ -2,6 +2,7 @@
  * Copyright 2004-present Facebook. All Rights Reserved.
  *
  * @providesModule AppStateIOSExample
+ * @flow
  */
 'use strict';
 
@@ -60,10 +61,10 @@ exports.examples = [
   {
     title: 'Subscribed AppStateIOS:',
     description: 'This changes according to the current state, so you can only ever see it rendered as "active"',
-    render() { return <AppStateSubscription showCurrentOnly={true} />; }
+    render(): ReactElement { return <AppStateSubscription showCurrentOnly={true} />; }
   },
   {
     title: 'Previous states:',
-    render() { return <AppStateSubscription showCurrentOnly={false} />; }
+    render(): ReactElement { return <AppStateSubscription showCurrentOnly={false} />; }
   },
 ];
diff --git a/Examples/UIExplorer/AsyncStorageExample.js b/Examples/UIExplorer/AsyncStorageExample.js
index 3a2579fa7..6064147fd 100644
--- a/Examples/UIExplorer/AsyncStorageExample.js
+++ b/Examples/UIExplorer/AsyncStorageExample.js
@@ -1,5 +1,6 @@
 /**
  * Copyright 2004-present Facebook. All Rights Reserved.
+ * @flow
  */
 'use strict';
 
@@ -98,6 +99,6 @@ exports.description = 'Asynchronous local disk storage.';
 exports.examples = [
   {
     title: 'Basics - getItem, setItem, removeItem',
-    render() { return <BasicStorageExample />; }
+    render(): ReactElement { return <BasicStorageExample />; }
   },
 ];
diff --git a/Examples/UIExplorer/CameraRollExample.ios.js b/Examples/UIExplorer/CameraRollExample.ios.js
index 7be014a33..dbc817bf5 100644
--- a/Examples/UIExplorer/CameraRollExample.ios.js
+++ b/Examples/UIExplorer/CameraRollExample.ios.js
@@ -1,5 +1,6 @@
 /**
  * Copyright 2004-present Facebook. All Rights Reserved.
+ * @flow
  */
 'use strict';
 
@@ -108,6 +109,6 @@ exports.description = 'Example component that uses CameraRoll to list user\'s ph
 exports.examples = [
   {
     title: 'Photos',
-    render() { return <CameraRollExample />; }
+    render(): ReactElement { return <CameraRollExample />; }
   }
 ];
diff --git a/Examples/UIExplorer/CameraRollView.ios.js b/Examples/UIExplorer/CameraRollView.ios.js
index c8a9a2829..2e1364eed 100644
--- a/Examples/UIExplorer/CameraRollView.ios.js
+++ b/Examples/UIExplorer/CameraRollView.ios.js
@@ -2,6 +2,7 @@
  * Copyright 2004-present Facebook. All Rights Reserved.
  *
  * @providesModule CameraRollView
+ * @flow
  */
 'use strict';
 
@@ -53,7 +54,7 @@ var propTypes = {
 var CameraRollView = React.createClass({
   propTypes: propTypes,
 
-  getDefaultProps: function() {
+  getDefaultProps: function(): Object {
     return {
       groupTypes: 'SavedPhotos',
       batchSize: 5,
@@ -75,9 +76,9 @@ var CameraRollView = React.createClass({
     var ds = new ListView.DataSource({rowHasChanged: this._rowHasChanged});
 
     return {
-      assets: [],
+      assets: ([]: Array<Image>),
       groupTypes: this.props.groupTypes,
-      lastCursor: null,
+      lastCursor: (null : ?string),
       noMore: false,
       loadingMore: false,
       dataSource: ds,
@@ -99,21 +100,21 @@ var CameraRollView = React.createClass({
     this.fetch();
   },
 
-  componentWillReceiveProps: function(nextProps) {
+  componentWillReceiveProps: function(nextProps: {groupTypes?: string}) {
     if (this.props.groupTypes !== nextProps.groupTypes) {
       this.fetch(true);
     }
   },
 
-  _fetch: function(clear) {
+  _fetch: function(clear?: boolean) {
     if (clear) {
       this.setState(this.getInitialState(), this.fetch);
       return;
     }
 
-    var fetchParams = {
+    var fetchParams: Object = {
       first: this.props.batchSize,
-      groupTypes: this.props.groupTypes,
+      groupTypes: this.props.groupTypes
     };
     if (this.state.lastCursor) {
       fetchParams.after = this.state.lastCursor;
@@ -126,7 +127,7 @@ var CameraRollView = React.createClass({
    * Fetches more images from the camera roll. If clear is set to true, it will
    * set the component to its initial state and re-fetch the images.
    */
-  fetch: function(clear) {
+  fetch: function(clear?: boolean) {
     if (!this.state.loadingMore) {
       this.setState({loadingMore: true}, () => { this._fetch(clear); });
     }
@@ -144,7 +145,7 @@ var CameraRollView = React.createClass({
     );
   },
 
-  _rowHasChanged: function(r1, r2) {
+  _rowHasChanged: function(r1: Array<Image>, r2: Array<Image>): boolean {
     if (r1.length !== r2.length) {
       return true;
     }
@@ -166,7 +167,7 @@ var CameraRollView = React.createClass({
   },
 
   // rowData is an array of images
-  _renderRow: function(rowData, sectionID, rowID)  {
+  _renderRow: function(rowData: Array<Image>, sectionID: string, rowID: string)  {
     var images = rowData.map((image) => {
       if (image === null) {
         return null;
@@ -181,9 +182,9 @@ var CameraRollView = React.createClass({
     );
   },
 
-  _appendAssets: function(data) {
+  _appendAssets: function(data: Object) {
     var assets = data.edges;
-    var newState = { loadingMore: false };
+    var newState: Object = { loadingMore: false };
 
     if (!data.page_info.has_next_page) {
       newState.noMore = true;
diff --git a/Examples/UIExplorer/DatePickerExample.js b/Examples/UIExplorer/DatePickerExample.js
index ab8b17625..4382f929f 100644
--- a/Examples/UIExplorer/DatePickerExample.js
+++ b/Examples/UIExplorer/DatePickerExample.js
@@ -1,5 +1,6 @@
 /**
  * Copyright 2004-present Facebook. All Rights Reserved.
+ * @flow
  */
 'use strict';
 
@@ -118,7 +119,7 @@ exports.description = 'Select dates and times using the native UIDatePicker.';
 exports.examples = [
 {
   title: '<DatePickerIOS>',
-  render: function() {
+  render: function(): ReactElement {
     return <DatePickerExample />;
   },
 }];
diff --git a/Examples/UIExplorer/GeolocationExample.js b/Examples/UIExplorer/GeolocationExample.js
index 78ba29b9d..38d720ba7 100644
--- a/Examples/UIExplorer/GeolocationExample.js
+++ b/Examples/UIExplorer/GeolocationExample.js
@@ -1,5 +1,6 @@
 /**
  * Copyright 2004-present Facebook. All Rights Reserved.
+ * @flow
  */
 /* eslint no-console: 0 */
 'use strict';
@@ -19,13 +20,15 @@ exports.description = 'Examples of using the Geolocation API.';
 exports.examples = [
   {
     title: 'navigator.geolocation',
-    render: function() {
+    render: function(): ReactElement {
       return <GeolocationExample />;
     },
   }
 ];
 
 var GeolocationExample = React.createClass({
+  watchID: (null: ?number),
+
   getInitialState: function() {
     return {
       initialPosition: 'unknown',
diff --git a/Examples/UIExplorer/LayoutExample.js b/Examples/UIExplorer/LayoutExample.js
index 2586694ec..ab8b3dc65 100644
--- a/Examples/UIExplorer/LayoutExample.js
+++ b/Examples/UIExplorer/LayoutExample.js
@@ -1,5 +1,6 @@
 /**
  * Copyright 2004-present Facebook. All Rights Reserved.
+ * @flow
  */
 'use strict';
 
diff --git a/Examples/UIExplorer/ListViewSimpleExample.js b/Examples/UIExplorer/ListViewSimpleExample.js
index c0a84fc54..b3f0f8c96 100644
--- a/Examples/UIExplorer/ListViewSimpleExample.js
+++ b/Examples/UIExplorer/ListViewSimpleExample.js
@@ -1,5 +1,6 @@
 /**
 * Copyright 2004-present Facebook. All Rights Reserved.
+* @flow
 */
 'use strict';
 
@@ -28,6 +29,8 @@ var ListViewSimpleExample = React.createClass({
     };
   },
 
+  _pressData: ({}: {[key: number]: boolean}),
+
   componentWillMount: function() {
     this._pressData = {};
   },
@@ -46,7 +49,7 @@ var ListViewSimpleExample = React.createClass({
     );
   },
 
-  _renderRow: function(rowData, sectionID, rowID) {
+  _renderRow: function(rowData: string, sectionID: number, rowID: number) {
     var rowHash = Math.abs(hashCode(rowData));
     var imgSource = {
       uri: THUMB_URLS[rowHash % THUMB_URLS.length],
@@ -66,7 +69,7 @@ var ListViewSimpleExample = React.createClass({
     );
   },
 
-  _genRows: function(pressData) {
+  _genRows: function(pressData: {[key: number]: boolean}): Array<string> {
     var dataBlob = [];
     for (var ii = 0; ii < 100; ii++) {
       var pressedText = pressData[ii] ? ' (pressed)' : '';
@@ -75,7 +78,7 @@ var ListViewSimpleExample = React.createClass({
     return dataBlob;
   },
 
-  _pressRow: function(rowID) {
+  _pressRow: function(rowID: number) {
     this._pressData[rowID] = !this._pressData[rowID];
     this.setState({dataSource: this.state.dataSource.cloneWithRows(
       this._genRows(this._pressData)
diff --git a/Libraries/Utilities/AlertIOS.js b/Libraries/Utilities/AlertIOS.js
index 8a342004c..3b2530f18 100644
--- a/Libraries/Utilities/AlertIOS.js
+++ b/Libraries/Utilities/AlertIOS.js
@@ -44,7 +44,7 @@ class AlertIOS {
   static alert(
     title: ?string,
     message: ?string,
-    buttons: ?Array<{
+    buttons?: Array<{
       text: ?string;
       onPress: ?Function;
     }>