diff --git a/include/boost/mp11/algorithm.hpp b/include/boost/mp11/algorithm.hpp
index 80a09c0..95d0e7f 100644
--- a/include/boost/mp11/algorithm.hpp
+++ b/include/boost/mp11/algorithm.hpp
@@ -309,6 +309,51 @@ template<class L, std::size_t N> using mp_take_c = typename detail::mp_take_impl
 
 template<class L, class N> using mp_take = typename detail::mp_take_impl<L, N>::type;
 
+// mp_replace<L, V, W>
+namespace detail
+{
+
+#if defined( BOOST_MSVC ) && BOOST_WORKAROUND( BOOST_MSVC, <= 1800 )
+
+template<class L, class V, class W> struct mp_replace_impl;
+
+template<template<class...> class L, class... T, class V, class W> struct mp_replace_impl<L<T...>, V, W>
+{
+    template<class A> struct _f { using type = mp_if<std::is_same<A, V>, W, A>; };
+
+    using type = L<typename _f<T>::type...>;
+};
+
+#else
+
+template<class L, class V, class W> struct mp_replace_impl
+{
+    template<class A> using _f = mp_if<std::is_same<A, V>, W, A>;
+
+    using type = mp_transform<_f, L>;
+};
+
+#endif
+
+} // namespace detail
+
+template<class L, class V, class W> using mp_replace = typename detail::mp_replace_impl<L, V, W>::type;
+
+// mp_replace_if<L, P, W>
+namespace detail
+{
+
+template<class L, template<class...> class P, class W> struct mp_replace_if_impl
+{
+    template<class T> using _f = mp_if<P<T>, W, T>;
+
+    using type = mp_transform<_f, L>;
+};
+
+} // namespace detail
+
+template<class L, template<class...> class P, class W> using mp_replace_if = typename detail::mp_replace_if_impl<L, P, W>::type;
+
 // mp_find<L, V>
 // mp_find_if<L, P>
 // mp_find_index<L, V>
@@ -318,8 +363,6 @@ template<class L, class N> using mp_take = typename detail::mp_take_impl<L, N>::
 // mp_remove_if<L, P>
 // mp_fold<L, V, F>
 // mp_reverse_fold<L, V, F>
-// mp_replace<L, V1, V2>?
-// mp_replace_if<L, P, V2>?
 // mp_partition<L, P>
 // mp_sort<L>
 
diff --git a/test/Jamfile.v2 b/test/Jamfile.v2
index e351fc4..1feb47e 100644
--- a/test/Jamfile.v2
+++ b/test/Jamfile.v2
@@ -38,6 +38,8 @@ run mp_drop.cpp : : : $(REQ) ;
 run mp_iota.cpp : : : $(REQ) ;
 run mp_at.cpp : : : $(REQ) ;
 run mp_take.cpp : : : $(REQ) ;
+run mp_replace.cpp : : : $(REQ) ;
+run mp_replace_if.cpp : : : $(REQ) ;
 
 # integral
 run integral.cpp : : : $(REQ) ;
diff --git a/test/mp_replace.cpp b/test/mp_replace.cpp
new file mode 100644
index 0000000..9562bfe
--- /dev/null
+++ b/test/mp_replace.cpp
@@ -0,0 +1,61 @@
+
+//  Copyright 2015 Peter Dimov.
+//
+// Distributed under the Boost Software License, Version 1.0.
+//
+// See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt
+
+
+#include <boost/mp11/algorithm.hpp>
+#include <boost/mp11/list.hpp>
+#include <boost/core/lightweight_test_trait.hpp>
+#include <type_traits>
+#include <tuple>
+#include <utility>
+
+struct X1 {};
+struct X2 {};
+struct X3 {};
+
+int main()
+{
+    using boost::mp_list;
+    using boost::mp_replace;
+
+    {
+        using L1 = mp_list<>;
+
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_replace<L1, void, int[]>, L1>));
+
+        using L2 = mp_list<X1, X2, X3, X2, X3, X3>;
+
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_replace<L2, void, int[]>, L2>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_replace<L2, X1, int[]>, mp_list<int[], X2, X3, X2, X3, X3>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_replace<L2, X2, int[]>, mp_list<X1, int[], X3, int[], X3, X3>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_replace<L2, X3, int[]>, mp_list<X1, X2, int[], X2, int[], int[]>>));
+    }
+
+    {
+        using L1 = std::tuple<>;
+
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_replace<L1, void, int[]>, L1>));
+
+        using L2 = std::tuple<X1, X2, X3, X2, X3, X3>;
+
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_replace<L2, void, int[]>, L2>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_replace<L2, X1, int[]>, std::tuple<int[], X2, X3, X2, X3, X3>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_replace<L2, X2, int[]>, std::tuple<X1, int[], X3, int[], X3, X3>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_replace<L2, X3, int[]>, std::tuple<X1, X2, int[], X2, int[], int[]>>));
+    }
+
+    {
+        using L2 = std::pair<X1, X2>;
+
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_replace<L2, void, int[]>, L2>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_replace<L2, X1, int[]>, std::pair<int[], X2>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_replace<L2, X2, int[]>, std::pair<X1, int[]>>));
+    }
+
+    return boost::report_errors();
+}
diff --git a/test/mp_replace_if.cpp b/test/mp_replace_if.cpp
new file mode 100644
index 0000000..c075494
--- /dev/null
+++ b/test/mp_replace_if.cpp
@@ -0,0 +1,57 @@
+
+//  Copyright 2015 Peter Dimov.
+//
+// Distributed under the Boost Software License, Version 1.0.
+//
+// See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt
+
+
+#include <boost/mp11/algorithm.hpp>
+#include <boost/mp11/list.hpp>
+#include <boost/core/lightweight_test_trait.hpp>
+#include <type_traits>
+#include <tuple>
+#include <utility>
+
+struct X1 {};
+
+int main()
+{
+    using boost::mp_list;
+    using boost::mp_replace_if;
+
+    {
+        using L1 = mp_list<>;
+
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_replace_if<L1, std::is_const, void>, L1>));
+
+        using L2 = mp_list<X1, X1 const, X1*, X1 const, X1*, X1*>;
+
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_replace_if<L2, std::is_volatile, void>, L2>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_replace_if<L2, std::is_const, void>, mp_list<X1, void, X1*, void, X1*, X1*>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_replace_if<L2, std::is_pointer, void>, mp_list<X1, X1 const, void, X1 const, void, void>>));
+    }
+
+    {
+        using L1 = std::tuple<>;
+
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_replace_if<L1, std::is_const, void>, L1>));
+
+        using L2 = std::tuple<X1, X1 const, X1*, X1 const, X1*, X1*>;
+
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_replace_if<L2, std::is_volatile, void>, L2>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_replace_if<L2, std::is_const, void>, std::tuple<X1, void, X1*, void, X1*, X1*>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_replace_if<L2, std::is_pointer, void>, std::tuple<X1, X1 const, void, X1 const, void, void>>));
+    }
+
+    {
+        using L2 = std::pair<X1 const, X1*>;
+
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_replace_if<L2, std::is_volatile, void>, L2>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_replace_if<L2, std::is_const, void>, std::pair<void, X1*>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_replace_if<L2, std::is_pointer, void>, std::pair<X1 const, void>>));
+    }
+
+    return boost::report_errors();
+}