diff --git a/atom/browser/api/atom_api_window.cc b/atom/browser/api/atom_api_window.cc
index 5d0a501629f8..077dffe0bc5c 100644
--- a/atom/browser/api/atom_api_window.cc
+++ b/atom/browser/api/atom_api_window.cc
@@ -42,14 +42,6 @@ struct Converter<atom::TaskbarHost::ThumbarButton> {
   }
 };
 
-template<>
-struct Converter<LPARAM> {
-  static v8::Local<v8::Value> ToV8(v8::Isolate* isolate,
-                                   LPARAM val) {
-    return ConvertToV8(isolate, static_cast<int64_t>(val));
-  }
-};
-
 }  // namespace mate
 #endif
 
@@ -198,7 +190,7 @@ void Window::OnExecuteWindowsCommand(const std::string& command_name) {
 }
 
 #if defined(OS_WIN)
-void Window::OnWindowMessage(UINT message, WPARAM w_param, LPARAM l_param) {
+void Window::OnWindowMessage(UINT message, WPARAM w_param, uint64_t l_param) {
   if (IsWindowMessageHooked(message)) {
     messages_callback_map_[message].Run(w_param, l_param);
   }
diff --git a/atom/browser/api/atom_api_window.h b/atom/browser/api/atom_api_window.h
index 870f8e134216..f4bc4cdba01a 100644
--- a/atom/browser/api/atom_api_window.h
+++ b/atom/browser/api/atom_api_window.h
@@ -77,8 +77,7 @@ class Window : public mate::TrackableObject<Window>,
   void OnExecuteWindowsCommand(const std::string& command_name) override;
 
   #if defined(OS_WIN)
-  void OnWindowMessage(UINT message, WPARAM w_param,
-                       LPARAM l_param) override;
+  void OnWindowMessage(UINT message, WPARAM w_param, uint64_t l_param) override;
   #endif
 
   // mate::Wrappable:
@@ -150,7 +149,7 @@ class Window : public mate::TrackableObject<Window>,
   void SetAspectRatio(double aspect_ratio, mate::Arguments* args);
 
 #if defined(OS_WIN)
-  typedef base::Callback<void(WPARAM, LPARAM)> MessageCallback;
+  typedef base::Callback<void(WPARAM, uint64_t)> MessageCallback;
   typedef std::map<UINT, MessageCallback> MessageCallbackMap;
   MessageCallbackMap messages_callback_map_;
 
diff --git a/atom/browser/native_window.cc b/atom/browser/native_window.cc
index e3abed473e7d..6e38f4028745 100644
--- a/atom/browser/native_window.cc
+++ b/atom/browser/native_window.cc
@@ -467,8 +467,9 @@ void NativeWindow::NotifyWindowExecuteWindowsCommand(
 #if defined(OS_WIN)
 void NativeWindow::NotifyWindowMessage(UINT message, WPARAM w_param,
                                        LPARAM l_param) {
-  FOR_EACH_OBSERVER(NativeWindowObserver, observers_,
-                    OnWindowMessage(message, w_param, l_param));
+  FOR_EACH_OBSERVER(
+      NativeWindowObserver, observers_,
+      OnWindowMessage(message, w_param, static_cast<uint64_t>(l_param)));
 }
 #endif
 
diff --git a/atom/browser/native_window_observer.h b/atom/browser/native_window_observer.h
index 54004a300d94..240a7277fa09 100644
--- a/atom/browser/native_window_observer.h
+++ b/atom/browser/native_window_observer.h
@@ -61,7 +61,7 @@ class NativeWindowObserver {
 
   // Called when window message received
   #if defined(OS_WIN)
-  virtual void OnWindowMessage(UINT message, WPARAM w_param, LPARAM l_param) {}
+  virtual void OnWindowMessage(UINT message, WPARAM wparam, uint64_t lparam) {}
   #endif
 
   // Called when renderer is hung.