diff --git a/src/msw/textctrl.cpp b/src/msw/textctrl.cpp
index ddc7f78b55..930b37cd6d 100644
--- a/src/msw/textctrl.cpp
+++ b/src/msw/textctrl.cpp
@@ -1023,7 +1023,7 @@ wxTextCtrl::StreamOut(wxFontEncoding encoding, bool selectionOnly) const
 
     EDITSTREAM eds;
     wxZeroMemory(eds);
-    eds.dwCookie = (DWORD)&data;
+    eds.dwCookie = (DWORD_PTR)&data;
     eds.pfnCallback = wxRichEditStreamOut;
 
     ::SendMessage