diff --git a/include/boost/type_index/stl_type_index.hpp b/include/boost/type_index/stl_type_index.hpp
index 4041753..dc43c65 100644
--- a/include/boost/type_index/stl_type_index.hpp
+++ b/include/boost/type_index/stl_type_index.hpp
@@ -40,7 +40,7 @@
 #include <boost/mpl/if.hpp>
 #include <boost/mpl/or.hpp>
 
-#if !(_MSC_VER > 1600 || (__GNUC__ == 4 && __GNUC_MINOR__ > 5 && defined(__GXX_EXPERIMENTAL_CXX0X__)))
+#if !((defined(_MSC_VER) && _MSC_VER > 1600) || (__GNUC__ == 4 && __GNUC_MINOR__ > 5 && defined(__GXX_EXPERIMENTAL_CXX0X__)))
 #   include <boost/functional/hash/hash.hpp>
 #endif