diff --git a/CMakeLists.txt b/CMakeLists.txt
index 14ef755276..c792387031 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -263,7 +263,7 @@ else()
   if (CYGWIN)
     add_definitions(-DCygwin)
   else()
-    add_definitions(-DWin32)
+    add_definitions(-DWIN32)
   endif()
 endif()