diff --git a/dom/src/base/nsDOMClassInfo.cpp b/dom/src/base/nsDOMClassInfo.cpp
index 4a9fa65ccb75..47466c9dd30a 100644
--- a/dom/src/base/nsDOMClassInfo.cpp
+++ b/dom/src/base/nsDOMClassInfo.cpp
@@ -157,7 +157,7 @@
 #endif
 
 // Oh, did I mention that I hate Microsoft for doing this to me?
-#ifdef WINCE
+#ifdef XP_WIN
 #undef GetClassName
 #endif