diff --git a/include/boost/type_traits/integral_constant.hpp b/include/boost/type_traits/integral_constant.hpp
index dac784f..ae2448d 100644
--- a/include/boost/type_traits/integral_constant.hpp
+++ b/include/boost/type_traits/integral_constant.hpp
@@ -77,6 +77,7 @@ namespace boost{
    struct integral_constant<bool, val>
    {
       typedef mpl::integral_c_tag tag;
+      typedef bool value_type;
       typedef integral_constant<bool, val> type;
       static const bool value = val;
       //