diff --git a/types/react-navigation/index.d.ts b/types/react-navigation/index.d.ts
index 6b821586dd..e8740523a6 100644
--- a/types/react-navigation/index.d.ts
+++ b/types/react-navigation/index.d.ts
@@ -6,6 +6,7 @@
 //                 abrahambotros <https://github.com/abrahambotros>
 //                 petejkim <https://github.com/petejkim>
 //                 Kyle Roach <https://github.com/iRoachie>
+//                 phanalpha <https://github.com/phanalpha>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 // TypeScript Version: 2.3
 
@@ -87,7 +88,7 @@ export type NavigationLeafRoute<Params> = {
    * Params passed to this route when navigating to it,
    * e.g. `{ car_id: 123 }` in a route that displays a car.
    */
-  params?: Params,
+  params: Params,
 };
 
 export type NavigationStateRoute<NavigationLeafRouteParams> = NavigationLeafRoute<NavigationLeafRouteParams> & {
@@ -263,7 +264,7 @@ export type NavigationStackScreenOptions = NavigationScreenOptions & {
   headerTitleStyle?: Style,
   headerTintColor?: string,
   headerLeft?: React.ReactElement<any>,
-  headerBackTitle?: string,
+  headerBackTitle?: string | null,
   headerTruncatedBackTitle?: string,
   headerBackTitleStyle?: Style,
   headerPressColorAndroid?: string,
@@ -676,3 +677,22 @@ export interface NavigationScreenProps<Params> {
 /**
  * END CUSTOM CONVENIENCE INTERFACES
  */
+
+
+/*
+ * Header
+ */
+
+// src/views/HeaderBackButton.js
+
+export interface HeaderBackButtonProps {
+  onPress?: () => void,
+  pressColorAndroid?: string,
+  title?: string,
+  titleStyle?: TextStyle,
+  tintColor?: string,
+  truncatedTitle?: string,
+  width?: number,
+}
+
+export const HeaderBackButton: React.ComponentClass<HeaderBackButtonProps>;
diff --git a/types/react-navigation/react-navigation-tests.tsx b/types/react-navigation/react-navigation-tests.tsx
index 1840fd7ccf..caa8b37843 100644
--- a/types/react-navigation/react-navigation-tests.tsx
+++ b/types/react-navigation/react-navigation-tests.tsx
@@ -27,6 +27,7 @@ import {
     TabNavigatorConfig,
     Transitioner,
     addNavigationHelpers,
+    HeaderBackButton,
 } from 'react-navigation';
 
 // Constants
@@ -97,6 +98,9 @@ class NextScreen extends React.Component<NextScreenProps, {}> {
     }
 }
 
+const navigationOptions = {
+    headerBackTitle: null,
+};
 const initialRouteParams: StartScreenNavigationParams = {
     id: 1,
     s: "Start",
@@ -116,6 +120,7 @@ export const AppNavigator = StackNavigator(
     {
         initialRouteName: ROUTE_NAME_START_SCREEN,
         initialRouteParams,
+        navigationOptions,
     },
 );
 
@@ -227,6 +232,32 @@ class CustomTransitioner extends React.Component<CustomTransitionerProps, null>
     }
 }
 
+/**
+ * Header
+ */
+function renderHeaderBackButton(schema: string): JSX.Element {
+    switch ( schema ) {
+        case 'compact':
+            return (
+                <HeaderBackButton />
+            );
+
+        default:
+            return (
+                <HeaderBackButton
+                    onPress={() => 'noop'}
+                    pressColorAndroid="#ccc"
+                    title="Press Me"
+                    titleStyle={{ color: '#333' }}
+                    tintColor="#2196f3"
+                    truncatedTitle="Press"
+                    width={85}
+                />
+            );
+    }
+}
+
+
 const initAction: NavigationInitAction = NavigationActions.init({
     params: {
         foo: "bar"
diff --git a/types/react-navigation/tsconfig.json b/types/react-navigation/tsconfig.json
index ad15863a78..bbf721c233 100644
--- a/types/react-navigation/tsconfig.json
+++ b/types/react-navigation/tsconfig.json
@@ -7,7 +7,7 @@
     ],
     "noImplicitAny": true,
     "noImplicitThis": true,
-    "strictNullChecks": false,
+    "strictNullChecks": true,
     "baseUrl": "../",
     "jsx": "react",
     "typeRoots": [