diff --git a/packager/react-packager/src/DependencyResolver/haste/DependencyGraph/__tests__/DependencyGraph-test.js b/packager/react-packager/src/DependencyResolver/haste/DependencyGraph/__tests__/DependencyGraph-test.js
index f42f6f8a1..40c159796 100644
--- a/packager/react-packager/src/DependencyResolver/haste/DependencyGraph/__tests__/DependencyGraph-test.js
+++ b/packager/react-packager/src/DependencyResolver/haste/DependencyGraph/__tests__/DependencyGraph-test.js
@@ -674,6 +674,296 @@ describe('DependencyGraph', function() {
           ]);
       });
     });
+
+    pit('should support simple browser field in packages', function() {
+      var root = '/root';
+      fs.__setMockFilesystem({
+        'root': {
+          'index.js': [
+            '/**',
+            ' * @providesModule index',
+            ' */',
+            'require("aPackage")',
+          ].join('\n'),
+          'aPackage': {
+            'package.json': JSON.stringify({
+              name: 'aPackage',
+              main: 'main.js',
+              browser: 'client.js',
+            }),
+            'main.js': 'some other code',
+            'client.js': 'some code',
+          }
+        }
+      });
+
+      var dgraph = new DependencyGraph({
+        roots: [root],
+        fileWatcher: fileWatcher
+      });
+      return dgraph.load().then(function() {
+        expect(dgraph.getOrderedDependencies('/root/index.js'))
+          .toEqual([
+            { id: 'index', altId: '/root/index.js',
+              path: '/root/index.js',
+              dependencies: ['aPackage']
+            },
+            { id: 'aPackage/client',
+              path: '/root/aPackage/client.js',
+              dependencies: []
+            },
+          ]);
+      });
+    });
+
+    pit('should supportbrowser field in packages w/o .js ext', function() {
+      var root = '/root';
+      fs.__setMockFilesystem({
+        'root': {
+          'index.js': [
+            '/**',
+            ' * @providesModule index',
+            ' */',
+            'require("aPackage")',
+          ].join('\n'),
+          'aPackage': {
+            'package.json': JSON.stringify({
+              name: 'aPackage',
+              main: 'main.js',
+              browser: 'client',
+            }),
+            'main.js': 'some other code',
+            'client.js': 'some code',
+          }
+        }
+      });
+
+      var dgraph = new DependencyGraph({
+        roots: [root],
+        fileWatcher: fileWatcher
+      });
+      return dgraph.load().then(function() {
+        expect(dgraph.getOrderedDependencies('/root/index.js'))
+          .toEqual([
+            { id: 'index', altId: '/root/index.js',
+              path: '/root/index.js',
+              dependencies: ['aPackage']
+            },
+            { id: 'aPackage/client',
+              path: '/root/aPackage/client.js',
+              dependencies: []
+            },
+          ]);
+      });
+    });
+
+    pit('should support mapping main in browser field json', function() {
+      var root = '/root';
+      fs.__setMockFilesystem({
+        'root': {
+          'index.js': [
+            '/**',
+            ' * @providesModule index',
+            ' */',
+            'require("aPackage")',
+          ].join('\n'),
+          'aPackage': {
+            'package.json': JSON.stringify({
+              name: 'aPackage',
+              main: './main.js',
+              browser: {
+                './main.js': './client.js',
+              },
+            }),
+            'main.js': 'some other code',
+            'client.js': 'some code',
+          }
+        }
+      });
+
+      var dgraph = new DependencyGraph({
+        roots: [root],
+        fileWatcher: fileWatcher
+      });
+      return dgraph.load().then(function() {
+        expect(dgraph.getOrderedDependencies('/root/index.js'))
+          .toEqual([
+            { id: 'index', altId: '/root/index.js',
+              path: '/root/index.js',
+              dependencies: ['aPackage']
+            },
+            { id: 'aPackage/client',
+              path: '/root/aPackage/client.js',
+              dependencies: []
+            },
+          ]);
+      });
+    });
+
+    pit('should work do correct browser mapping w/o js ext', function() {
+      var root = '/root';
+      fs.__setMockFilesystem({
+        'root': {
+          'index.js': [
+            '/**',
+            ' * @providesModule index',
+            ' */',
+            'require("aPackage")',
+          ].join('\n'),
+          'aPackage': {
+            'package.json': JSON.stringify({
+              name: 'aPackage',
+              main: './main.js',
+              browser: {
+                './main': './client.js',
+              },
+            }),
+            'main.js': 'some other code',
+            'client.js': 'some code',
+          }
+        }
+      });
+
+      var dgraph = new DependencyGraph({
+        roots: [root],
+        fileWatcher: fileWatcher
+      });
+      return dgraph.load().then(function() {
+        expect(dgraph.getOrderedDependencies('/root/index.js'))
+          .toEqual([
+            { id: 'index', altId: '/root/index.js',
+              path: '/root/index.js',
+              dependencies: ['aPackage']
+            },
+            { id: 'aPackage/client',
+              path: '/root/aPackage/client.js',
+              dependencies: []
+            },
+          ]);
+      });
+    });
+
+    pit('should support browser mapping of files', function() {
+      var root = '/root';
+      fs.__setMockFilesystem({
+        'root': {
+          'index.js': [
+            '/**',
+            ' * @providesModule index',
+            ' */',
+            'require("aPackage")',
+          ].join('\n'),
+          'aPackage': {
+            'package.json': JSON.stringify({
+              name: 'aPackage',
+              main: './main.js',
+              browser: {
+                './main': './client.js',
+                './node.js': './not-node.js',
+                './not-browser': './browser.js',
+                './dir/server.js': './dir/client',
+              },
+            }),
+            'main.js': 'some other code',
+            'client.js': 'require("./node")\nrequire("./dir/server.js")',
+            'not-node.js': 'require("./not-browser")',
+            'not-browser.js': 'require("./dir/server")',
+            'browser.js': 'some browser code',
+            'dir': {
+              'server.js': 'some node code',
+              'client.js': 'some browser code',
+            }
+          }
+        }
+      });
+
+      var dgraph = new DependencyGraph({
+        roots: [root],
+        fileWatcher: fileWatcher
+      });
+      return dgraph.load().then(function() {
+        expect(dgraph.getOrderedDependencies('/root/index.js'))
+          .toEqual([
+            { id: 'index', altId: '/root/index.js',
+              path: '/root/index.js',
+              dependencies: ['aPackage']
+            },
+            { id: 'aPackage/client',
+              path: '/root/aPackage/client.js',
+              dependencies: ['./node', './dir/server.js']
+            },
+            { id: 'aPackage/not-node',
+              path: '/root/aPackage/not-node.js',
+              dependencies: ['./not-browser']
+            },
+            { id: 'aPackage/browser',
+              path: '/root/aPackage/browser.js',
+              dependencies: []
+            },
+            { id: 'aPackage/dir/client',
+              path: '/root/aPackage/dir/client.js',
+              dependencies: []
+            },
+          ]);
+      });
+    });
+
+    pit('should support browser mapping for packages', function() {
+      var root = '/root';
+      fs.__setMockFilesystem({
+        'root': {
+          'index.js': [
+            '/**',
+            ' * @providesModule index',
+            ' */',
+            'require("aPackage")',
+          ].join('\n'),
+          'aPackage': {
+            'package.json': JSON.stringify({
+              name: 'aPackage',
+              browser: {
+                'node-package': 'browser-package',
+              }
+            }),
+            'index.js': 'require("node-package")',
+            'node-package': {
+              'package.json': JSON.stringify({
+                'name': 'node-package',
+              }),
+              'index.js': 'some node code',
+            },
+            'browser-package': {
+              'package.json': JSON.stringify({
+                'name': 'browser-package',
+              }),
+              'index.js': 'some browser code',
+            },
+          }
+        }
+      });
+
+      var dgraph = new DependencyGraph({
+        roots: [root],
+        fileWatcher: fileWatcher
+      });
+      return dgraph.load().then(function() {
+        expect(dgraph.getOrderedDependencies('/root/index.js'))
+          .toEqual([
+            { id: 'index', altId: '/root/index.js',
+              path: '/root/index.js',
+              dependencies: ['aPackage']
+            },
+            { id: 'aPackage/index',
+              path: '/root/aPackage/index.js',
+              dependencies: ['node-package']
+            },
+            { id: 'browser-package/index',
+              path: '/root/aPackage/browser-package/index.js',
+              dependencies: []
+            },
+          ]);
+      });
+    });
   });
 
   describe('file watch updating', function() {
diff --git a/packager/react-packager/src/DependencyResolver/haste/DependencyGraph/index.js b/packager/react-packager/src/DependencyResolver/haste/DependencyGraph/index.js
index fbc7de712..d0ce699e4 100644
--- a/packager/react-packager/src/DependencyResolver/haste/DependencyGraph/index.js
+++ b/packager/react-packager/src/DependencyResolver/haste/DependencyGraph/index.js
@@ -168,15 +168,22 @@ DependecyGraph.prototype.resolveDependency = function(
   // Package relative modules starts with '.' or '..'.
   if (depModuleId[0] !== '.') {
 
-    // 1. `depModuleId` is simply a top-level `providesModule`.
-    // 2. `depModuleId` is a package module but given the full path from the
-    //     package, i.e. package_name/module_name
+    // Check if we need to map the dependency to something else via the
+    // `browser` field in package.json
+    var fromPackageJson = this._lookupPackage(fromModule.path);
+    if (fromPackageJson && fromPackageJson.browser &&
+        fromPackageJson.browser[depModuleId]) {
+      depModuleId = fromPackageJson.browser[depModuleId];
+    }
+
+    // `depModuleId` is simply a top-level `providesModule`.
+    // `depModuleId` is a package module but given the full path from the
+    //  package, i.e. package_name/module_name
     if (this._moduleById[sansExtJs(depModuleId)]) {
       return this._moduleById[sansExtJs(depModuleId)];
     }
 
-    // 3. `depModuleId` is a package and it's depending on the "main"
-    //    resolution.
+    // `depModuleId` is a package and it's depending on the "main" resolution.
     packageJson = this._packagesById[depModuleId];
 
     // We are being forgiving here and raising an error because we could be
@@ -190,7 +197,25 @@ DependecyGraph.prototype.resolveDependency = function(
       return null;
     }
 
-    var main = packageJson.main || 'index';
+    var main;
+
+    // We prioritize the `browser` field if it's a module path.
+    if (typeof packageJson.browser === 'string') {
+      main = packageJson.browser;
+    } else {
+      main = packageJson.main || 'index';
+    }
+
+    // If there is a mapping for main in the `browser` field.
+    if (packageJson.browser && typeof packageJson.browser === 'object') {
+      var tmpMain = packageJson.browser[main] ||
+            packageJson.browser[withExtJs(main)] ||
+            packageJson.browser[sansExtJs(main)];
+      if (tmpMain) {
+        main = tmpMain;
+      }
+    }
+
     modulePath = withExtJs(path.join(packageJson._root, main));
     dep = this._graph[modulePath];
 
@@ -207,8 +232,7 @@ DependecyGraph.prototype.resolveDependency = function(
     return dep;
   } else {
 
-    // 4. `depModuleId` is a module defined in a package relative to
-    //    `fromModule`.
+    // `depModuleId` is a module defined in a package relative to `fromModule`.
     packageJson = this._lookupPackage(fromModule.path);
 
     if (packageJson == null) {
@@ -224,12 +248,23 @@ DependecyGraph.prototype.resolveDependency = function(
     var dir = path.dirname(fromModule.path);
     modulePath = path.join(dir, depModuleId);
 
+    if (packageJson.browser && typeof packageJson.browser === 'object') {
+      var relPath = './' + path.relative(packageJson._root, modulePath);
+      var tmpModulePath = packageJson.browser[withExtJs(relPath)] ||
+            packageJson.browser[sansExtJs(relPath)];
+      if (tmpModulePath) {
+        modulePath = path.join(packageJson._root, tmpModulePath);
+      }
+    }
+
+    // JS modules can be required without extensios.
     if (this._assetExts.indexOf(extname(modulePath)) === -1) {
       modulePath = withExtJs(modulePath);
     }
 
     dep = this._graph[modulePath];
 
+    // Maybe the dependency is a directory and there is an index.js inside it.
     if (dep == null) {
       modulePath = path.join(dir, depModuleId, 'index.js');
     }