diff --git a/include/boost/smart_ptr/detail/lwm_win32_cs.hpp b/include/boost/smart_ptr/detail/lwm_win32_cs.hpp
index 00477e4..a93cf09 100644
--- a/include/boost/smart_ptr/detail/lwm_win32_cs.hpp
+++ b/include/boost/smart_ptr/detail/lwm_win32_cs.hpp
@@ -11,12 +11,15 @@
 //  boost/detail/lwm_win32_cs.hpp
 //
 //  Copyright (c) 2002, 2003 Peter Dimov
+//  Copyright (c) Microsoft Corporation 2014
 //
 // 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/predef.h>
+
 #ifdef BOOST_USE_WINDOWS_H
 #  include <windows.h>
 #endif
@@ -43,7 +46,11 @@ struct critical_section
 #endif
 };
 
+#if BOOST_PLAT_WINDOWS_RUNTIME
+extern "C" __declspec(dllimport) void __stdcall InitializeCriticalSectionEx(critical_section *, unsigned long, unsigned long);
+#else
 extern "C" __declspec(dllimport) void __stdcall InitializeCriticalSection(critical_section *);
+#endif
 extern "C" __declspec(dllimport) void __stdcall EnterCriticalSection(critical_section *);
 extern "C" __declspec(dllimport) void __stdcall LeaveCriticalSection(critical_section *);
 extern "C" __declspec(dllimport) void __stdcall DeleteCriticalSection(critical_section *);
@@ -67,7 +74,11 @@ public:
 
     lightweight_mutex()
     {
+#if BOOST_PLAT_WINDOWS_RUNTIME
+        InitializeCriticalSectionEx(&cs_, 4000, 0);
+#else
         InitializeCriticalSection(&cs_);
+#endif
     }
 
     ~lightweight_mutex()
diff --git a/include/boost/smart_ptr/detail/yield_k.hpp b/include/boost/smart_ptr/detail/yield_k.hpp
index 14af524..9f4496b 100644
--- a/include/boost/smart_ptr/detail/yield_k.hpp
+++ b/include/boost/smart_ptr/detail/yield_k.hpp
@@ -11,6 +11,7 @@
 //  yield_k.hpp
 //
 //  Copyright (c) 2008 Peter Dimov
+//  Copyright (c) Microsoft Corporation 2014
 //
 //  void yield( unsigned k );
 //
@@ -24,6 +25,11 @@
 //
 
 #include <boost/config.hpp>
+#include <boost/predef.h>
+
+#if BOOST_PLAT_WINDOWS_RUNTIME
+#include <thread>
+#endif
 
 // BOOST_SMT_PAUSE
 
@@ -53,7 +59,7 @@ namespace boost
 namespace detail
 {
 
-#if !defined( BOOST_USE_WINDOWS_H )
+#if !defined( BOOST_USE_WINDOWS_H ) && !BOOST_PLAT_WINDOWS_RUNTIME
   extern "C" void __stdcall Sleep( unsigned long ms );
 #endif
 
@@ -68,6 +74,7 @@ inline void yield( unsigned k )
         BOOST_SMT_PAUSE
     }
 #endif
+#if !BOOST_PLAT_WINDOWS_RUNTIME
     else if( k < 32 )
     {
         Sleep( 0 );
@@ -76,6 +83,13 @@ inline void yield( unsigned k )
     {
         Sleep( 1 );
     }
+#else
+    else
+    {
+        // Sleep isn't supported on the Windows Runtime.
+        std::this_thread::yield();
+    }
+#endif
 }
 
 } // namespace detail