diff --git a/brightray/browser/browser_client.cc b/brightray/browser/browser_client.cc
index 63fb78257bf3..2d02e826dda4 100644
--- a/brightray/browser/browser_client.cc
+++ b/brightray/browser/browser_client.cc
@@ -48,4 +48,11 @@ void BrowserClient::ShowDesktopNotification(
   notification_presenter()->ShowNotification(params, render_process_id, render_view_id);
 }
 
+void BrowserClient::CancelDesktopNotification(
+    int render_process_id,
+    int render_view_id,
+    int notification_id) {
+  notification_presenter()->CancelNotification(render_process_id, render_view_id, notification_id);
+}
+
 }
diff --git a/brightray/browser/browser_client.h b/brightray/browser/browser_client.h
index 38983dd47fb8..33fea3dea320 100644
--- a/brightray/browser/browser_client.h
+++ b/brightray/browser/browser_client.h
@@ -35,6 +35,10 @@ private:
       int render_process_id,
       int render_view_id,
       bool worker) OVERRIDE;
+  virtual void CancelDesktopNotification(
+      int render_process_id,
+      int render_view_id,
+      int notification_id) OVERRIDE;
 
   BrowserMainParts* browser_main_parts_;
   scoped_ptr<NotificationPresenter> notification_presenter_;
diff --git a/brightray/browser/notification_presenter.h b/brightray/browser/notification_presenter.h
index f2b6e7ea44cf..a106edab208d 100644
--- a/brightray/browser/notification_presenter.h
+++ b/brightray/browser/notification_presenter.h
@@ -17,6 +17,10 @@ class NotificationPresenter {
       const content::ShowDesktopNotificationHostMsgParams&,
       int render_process_id,
       int render_view_id) = 0;
+  virtual void CancelNotification(
+      int render_process_id,
+      int render_view_id,
+      int notification_id) = 0;
 };
 
 }
diff --git a/brightray/browser/notification_presenter_mac.h b/brightray/browser/notification_presenter_mac.h
index 77da8cf0766c..5cd2c87e40a4 100644
--- a/brightray/browser/notification_presenter_mac.h
+++ b/brightray/browser/notification_presenter_mac.h
@@ -1,9 +1,15 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Copyright (c) 2013 Adam Roben <adam@roben.org>. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE-CHROMIUM file.
+
 #ifndef BRIGHTRAY_BROWSER_NOTIFICATION_PRESENTER_MAC_H_
 #define BRIGHTRAY_BROWSER_NOTIFICATION_PRESENTER_MAC_H_
 
 #import "browser/notification_presenter.h"
 
 #import "base/memory/scoped_nsobject.h"
+#import <map>
 
 @class BRYUserNotificationCenterDelegate;
 
@@ -18,8 +24,13 @@ class NotificationPresenterMac : public NotificationPresenter {
       const content::ShowDesktopNotificationHostMsgParams&,
       int render_process_id,
       int render_view_id) OVERRIDE;
+  virtual void CancelNotification(
+      int render_process_id,
+      int render_view_id,
+      int notification_id) OVERRIDE;
 
  private:
+  std::map<std::string, scoped_nsobject<NSUserNotification>> notification_map_;
   scoped_nsobject<BRYUserNotificationCenterDelegate> delegate_;
 };
 
diff --git a/brightray/browser/notification_presenter_mac.mm b/brightray/browser/notification_presenter_mac.mm
index 49a33561459b..02ca2927fe38 100644
--- a/brightray/browser/notification_presenter_mac.mm
+++ b/brightray/browser/notification_presenter_mac.mm
@@ -1,5 +1,11 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Copyright (c) 2013 Adam Roben <adam@roben.org>. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE-CHROMIUM file.
+
 #import "browser/notification_presenter_mac.h"
 
+#import "base/stringprintf.h"
 #import "base/strings/sys_string_conversions.h"
 #import "content/public/browser/render_view_host.h"
 #import "content/public/common/show_desktop_notification_params.h"
@@ -19,12 +25,12 @@ NSString * const kNotificationIDKey = @"NotificationID";
 
 struct NotificationID {
   NotificationID(
-      const content::ShowDesktopNotificationHostMsgParams& params,
       int render_process_id,
-      int render_view_id)
+      int render_view_id,
+      int notification_id)
       : render_process_id(render_process_id),
         render_view_id(render_view_id),
-        notification_id(params.notification_id) {
+        notification_id(notification_id) {
   }
 
   NotificationID(NSUserNotification* notification)
@@ -33,6 +39,10 @@ struct NotificationID {
         notification_id([[notification.userInfo objectForKey:kNotificationIDKey] intValue]) {
   }
 
+  std::string GetID() {
+    return base::StringPrintf("%d:%d:%d", render_process_id, render_view_id, notification_id);
+  }
+
   NSDictionary* GetUserInfo() {
     return @{
       kRenderProcessIDKey: @(render_process_id),
@@ -53,7 +63,7 @@ scoped_nsobject<NSUserNotification> CreateUserNotification(
   auto notification = [[NSUserNotification alloc] init];
   notification.title = base::SysUTF16ToNSString(params.title);
   notification.informativeText = base::SysUTF16ToNSString(params.body);
-  notification.userInfo = NotificationID(params, render_process_id, render_view_id).GetUserInfo();
+  notification.userInfo = NotificationID(render_process_id, render_view_id, params.notification_id).GetUserInfo();
 
   return scoped_nsobject<NSUserNotification>(notification);
 }
@@ -77,9 +87,39 @@ void NotificationPresenterMac::ShowNotification(
     int render_process_id,
     int render_view_id) {
   auto notification = CreateUserNotification(params, render_process_id, render_view_id);
+  notification_map_.insert(std::make_pair(NotificationID(notification).GetID(), notification));
   [NSUserNotificationCenter.defaultUserNotificationCenter deliverNotification:notification];
 }
 
+void NotificationPresenterMac::CancelNotification(
+    int render_process_id,
+    int render_view_id,
+    int notification_id) {
+  auto found = notification_map_.find(NotificationID(render_process_id, render_view_id, notification_id).GetID());
+  if (found == notification_map_.end())
+    return;
+
+  auto notification = found->second;
+
+  notification_map_.erase(found);
+
+  // Notifications in -deliveredNotifications aren't the same objects we passed to
+  // -deliverNotification:, but they will respond YES to -isEqual:.
+  auto center = NSUserNotificationCenter.defaultUserNotificationCenter;
+  for (NSUserNotification* deliveredNotification in center.deliveredNotifications) {
+    if (![notification isEqual:deliveredNotification])
+      continue;
+    [center removeDeliveredNotification:deliveredNotification];
+  }
+
+  NotificationID ID(notification);
+  auto host = content::RenderViewHost::FromID(ID.render_process_id, ID.render_view_id);
+  if (!host)
+    return;
+
+  host->DesktopNotificationPostClose(ID.notification_id, false);
+}
+
 }
 
 @implementation BRYUserNotificationCenterDelegate