diff --git a/include/boost/tuple/detail/tuple_basic.hpp b/include/boost/tuple/detail/tuple_basic.hpp
index 5a7de65..96fb5bd 100644
--- a/include/boost/tuple/detail/tuple_basic.hpp
+++ b/include/boost/tuple/detail/tuple_basic.hpp
@@ -94,7 +94,7 @@ namespace detail {
 template<class T>
 class generate_error;
 
-template<int N>
+template<std::size_t N>
 struct drop_front {
     template<class Tuple>
     struct apply {
@@ -128,14 +128,14 @@ struct drop_front<0> {
 
 #ifndef BOOST_NO_CV_SPECIALIZATIONS
 
-template<int N, class T>
+template<std::size_t N, class T>
 struct element
 {
   typedef BOOST_DEDUCED_TYPENAME detail::drop_front<N>::BOOST_NESTED_TEMPLATE
       apply<T>::type::head_type type;
 };
 
-template<int N, class T>
+template<std::size_t N, class T>
 struct element<N, const T>
 {
 private:
@@ -152,14 +152,14 @@ public:
 
 namespace detail {
 
-template<int N, class T, bool IsConst>
+template<std::size_t N, class T, bool IsConst>
 struct element_impl
 {
   typedef BOOST_DEDUCED_TYPENAME detail::drop_front<N>::BOOST_NESTED_TEMPLATE
       apply<T>::type::head_type type;
 };
 
-template<int N, class T>
+template<std::size_t N, class T>
 struct element_impl<N, T, true /* IsConst */>
 {
   typedef BOOST_DEDUCED_TYPENAME detail::drop_front<N>::BOOST_NESTED_TEMPLATE
@@ -170,7 +170,7 @@ struct element_impl<N, T, true /* IsConst */>
 } // end of namespace detail
 
 
-template<int N, class T>
+template<std::size_t N, class T>
 struct element:
   public detail::element_impl<N, T, ::boost::is_const<T>::value>
 {
@@ -211,7 +211,7 @@ template <class T> struct access_traits<T&> {
 
 // get function for non-const cons-lists, returns a reference to the element
 
-template<int N, class HT, class TT>
+template<std::size_t N, class HT, class TT>
 inline typename access_traits<
                   typename element<N, cons<HT, TT> >::type
                 >::non_const_type
@@ -225,7 +225,7 @@ get(cons<HT, TT>& c) {
 // get function for const cons-lists, returns a const reference to
 // the element. If the element is a reference, returns the reference
 // as such (that is, can return a non-const reference)
-template<int N, class HT, class TT>
+template<std::size_t N, class HT, class TT>
 inline typename access_traits<
                   typename element<N, cons<HT, TT> >::type
                 >::const_type
@@ -334,7 +334,7 @@ struct cons {
   }
 
   // get member functions (non-const and const)
-  template <int N>
+  template <std::size_t N>
   typename access_traits<
              typename element<N, cons<HT, TT> >::type
            >::non_const_type
@@ -342,7 +342,7 @@ struct cons {
     return boost::tuples::get<N>(*this); // delegate to non-member get
   }
 
-  template <int N>
+  template <std::size_t N>
   typename access_traits<
              typename element<N, cons<HT, TT> >::type
            >::const_type
@@ -404,7 +404,7 @@ struct cons<HT, null_type> {
   // is illformed if HT is a reference
   cons& operator=(const cons& u) { head = u.head; return *this; }
 
-  template <int N>
+  template <std::size_t N>
   typename access_traits<
              typename element<N, self_type>::type
             >::non_const_type
@@ -412,7 +412,7 @@ struct cons<HT, null_type> {
     return boost::tuples::get<N>(*this);
   }
 
-  template <int N>
+  template <std::size_t N>
   typename access_traits<
              typename element<N, self_type>::type
            >::const_type
@@ -425,27 +425,27 @@ struct cons<HT, null_type> {
 // templates for finding out the length of the tuple -------------------
 
 template<class T>
-struct length: boost::integral_constant<int, 1 + length<typename T::tail_type>::value>
+struct length: boost::integral_constant<std::size_t, 1 + length<typename T::tail_type>::value>
 {
 };
 
 template<>
-struct length<tuple<> >: boost::integral_constant<int, 0>
+struct length<tuple<> >: boost::integral_constant<std::size_t, 0>
 {
 };
 
 template<>
-struct length<tuple<> const>: boost::integral_constant<int, 0>
+struct length<tuple<> const>: boost::integral_constant<std::size_t, 0>
 {
 };
 
 template<>
-struct length<null_type>: boost::integral_constant<int, 0>
+struct length<null_type>: boost::integral_constant<std::size_t, 0>
 {
 };
 
 template<>
-struct length<null_type const>: boost::integral_constant<int, 0>
+struct length<null_type const>: boost::integral_constant<std::size_t, 0>
 {
 };