diff --git a/gfx/thebes/gfxPlatform.cpp b/gfx/thebes/gfxPlatform.cpp
index 40e6e799a0f..1957a7fed38 100644
--- a/gfx/thebes/gfxPlatform.cpp
+++ b/gfx/thebes/gfxPlatform.cpp
@@ -15,6 +15,11 @@
 
 #include "gfxPlatform.h"
 
+#ifdef XP_WIN
+#include <process.h>
+#define getpid _getpid
+#endif
+
 #include "nsXULAppAPI.h"
 #include "nsDirectoryServiceUtils.h"
 #include "nsDirectoryServiceDefs.h"