diff --git a/include/boost/integer.hpp b/include/boost/integer.hpp
index 3393c81..fc0b398 100644
--- a/include/boost/integer.hpp
+++ b/include/boost/integer.hpp
@@ -57,6 +57,8 @@ namespace boost
   //  no specializations for 0 and 5: requests for a type > long are in error
 #ifdef BOOST_HAS_LONG_LONG
   template<> struct int_least_helper<1> { typedef boost::long_long_type least; };
+#elif defined(BOOST_HAS_MS_INT64)
+  template<> struct int_least_helper<1> { typedef __int64 least; };
 #endif
   template<> struct int_least_helper<2> { typedef long least; };
   template<> struct int_least_helper<3> { typedef int least; };
@@ -64,6 +66,8 @@ namespace boost
   template<> struct int_least_helper<5> { typedef signed char least; };
 #ifdef BOOST_HAS_LONG_LONG
   template<> struct int_least_helper<6> { typedef boost::ulong_long_type least; };
+#elif defined(BOOST_HAS_MS_INT64)
+  template<> struct int_least_helper<6> { typedef unsigned __int64 least; };
 #endif
   template<> struct int_least_helper<7> { typedef unsigned long least; };
   template<> struct int_least_helper<8> { typedef unsigned int least; };
diff --git a/include/boost/integer_fwd.hpp b/include/boost/integer_fwd.hpp
index 01b0a08..e6045ca 100644
--- a/include/boost/integer_fwd.hpp
+++ b/include/boost/integer_fwd.hpp
@@ -77,12 +77,18 @@ template <  >
 template <  >
     class integer_traits< unsigned long >;
 
-#if !defined(BOOST_NO_INTEGRAL_INT64_T) && !defined(BOOST_NO_INT64_T) && (defined(BOOST_HAS_LONG_LONG) || defined(BOOST_HAS_MS_INT64))
+#if !defined(BOOST_NO_INTEGRAL_INT64_T) && !defined(BOOST_NO_INT64_T) && defined(BOOST_HAS_LONG_LONG)
 template <  >
-    class integer_traits<  ::boost::long_long_type>;
+class integer_traits<  ::boost::long_long_type>;
 
 template <  >
-    class integer_traits<  ::boost::ulong_long_type >;
+class integer_traits<  ::boost::ulong_long_type >;
+#elif !defined(BOOST_NO_INTEGRAL_INT64_T) && !defined(BOOST_NO_INT64_T) && defined(BOOST_HAS_MS_INT64)
+template <  >
+class integer_traits<__int64>;
+
+template <  >
+class integer_traits<unsigned __int64>;
 #endif