diff --git a/include/boost/static_assert.hpp b/include/boost/static_assert.hpp
index 0c9c5a5..d94ca80 100644
--- a/include/boost/static_assert.hpp
+++ b/include/boost/static_assert.hpp
@@ -16,6 +16,7 @@
 
 #include <boost/config.hpp>
 #include <boost/detail/workaround.hpp>
+#include <cstddef> //for std::size_t
 
 #if defined(__GNUC__) && !defined(__GXX_EXPERIMENTAL_CXX0X__)
 //
@@ -81,7 +82,7 @@ template <bool x> struct STATIC_ASSERTION_FAILURE;
 template <> struct STATIC_ASSERTION_FAILURE<true> { enum { value = 1 }; };
 
 // HP aCC cannot deal with missing names for template value parameters
-template<int x> struct static_assert_test{};
+template<std::size_t x> struct static_assert_test{};
 
 }