diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 6f2969f58fe1f5cccb714e4114511540735e4953..def5105d70958c38a02d0ab8673328efe52a2949 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,10 @@
+2009-12-31  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	* include/std/bitset (bitset<>::bitset(unsigned long long),
+	_Base_bitset<>::_Base_bitset(unsigned long long)): Add
+	in C++0x mode.
+	* testsuite/23_containers/bitset/cons/3.cc: New.
+
 2009-12-31  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	* include/std/type_traits: Fix minor stylistic nit.
diff --git a/libstdc++-v3/include/std/bitset b/libstdc++-v3/include/std/bitset
index 78843557e165af03502f0e3f644d6f305186cf66..06fdd3f4768f60abffe69ab6be2ca2faa3d84395 100644
--- a/libstdc++-v3/include/std/bitset
+++ b/libstdc++-v3/include/std/bitset
@@ -76,10 +76,18 @@ _GLIBCXX_BEGIN_NESTED_NAMESPACE(std, _GLIBCXX_STD_D)
       _Base_bitset()
       { _M_do_reset(); }
 
+#ifdef __GXX_EXPERIMENTAL_CXX0X__
+      _Base_bitset(unsigned long long __val)
+#else
       _Base_bitset(unsigned long __val)
+#endif
       {
 	_M_do_reset();
 	_M_w[0] = __val;
+#ifdef __GXX_EXPERIMENTAL_CXX0X__
+	if (sizeof(unsigned long long) > sizeof(unsigned long))
+	  _M_w[1] = __val >> _GLIBCXX_BITSET_BITS_PER_WORD;
+#endif
       }
 
       static size_t
@@ -359,7 +367,11 @@ _GLIBCXX_BEGIN_NESTED_NAMESPACE(std, _GLIBCXX_STD_D)
       : _M_w(0)
       { }
 
+#ifdef __GXX_EXPERIMENTAL_CXX0X__
+      _Base_bitset(unsigned long long __val)
+#else
       _Base_bitset(unsigned long __val)
+#endif
       : _M_w(__val)
       { }
 
@@ -491,7 +503,11 @@ _GLIBCXX_BEGIN_NESTED_NAMESPACE(std, _GLIBCXX_STD_D)
       _Base_bitset()
       { }
 
+#ifdef __GXX_EXPERIMENTAL_CXX0X__
+      _Base_bitset(unsigned long long)
+#else
       _Base_bitset(unsigned long)
+#endif
       { }
 
       static size_t
@@ -771,7 +787,11 @@ _GLIBCXX_BEGIN_NESTED_NAMESPACE(std, _GLIBCXX_STD_D)
       { }
 
       /// Initial bits bitwise-copied from a single word (others set to zero).
+#ifdef __GXX_EXPERIMENTAL_CXX0X__
+      bitset(unsigned long long __val)
+#else
       bitset(unsigned long __val)
+#endif
       : _Base(__val)
       { _M_do_sanitize(); }
 
diff --git a/libstdc++-v3/testsuite/23_containers/bitset/cons/3.cc b/libstdc++-v3/testsuite/23_containers/bitset/cons/3.cc
new file mode 100644
index 0000000000000000000000000000000000000000..b908068704b1905f5a75b645a92af8fc2a3e1f06
--- /dev/null
+++ b/libstdc++-v3/testsuite/23_containers/bitset/cons/3.cc
@@ -0,0 +1,62 @@
+// { dg-options "-std=gnu++0x" }
+
+// 2009-12-31  Paolo Carlini  <paolo.carlini@oracle.com>
+
+// Copyright (C) 2009 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#include <bitset>
+#include <testsuite_hooks.h>
+
+void test01()
+{
+  bool test __attribute__((unused)) = true;
+
+  const unsigned long long num0 = 0ULL;
+  std::bitset<0> bs0(num0);
+  VERIFY( bs0.to_ullong() == num0 );
+
+  const unsigned long long num1 = 215ULL;
+  std::bitset<32> bs1(num1);
+  VERIFY( bs1.to_ullong() == num1 );
+
+  const unsigned long long num2 = 215ULL;
+  std::bitset<64> bs2(num2);
+  VERIFY( bs2.to_ullong() == num2 );
+
+  const unsigned long long num3 = 343353215ULL;
+  std::bitset<32> bs3(num3);
+  VERIFY( bs3.to_ullong() == num3 );
+
+  const unsigned long long num4 = 343353215ULL;
+  std::bitset<64> bs4(num4);
+  VERIFY( bs4.to_ullong() == num4 );
+
+  const unsigned long long num5 = 13008719539498589283ULL;
+  std::bitset<64> bs5(num5);
+  VERIFY( bs5.to_ullong() == num5 );
+
+  const unsigned long long num6 = 13008719539498589283ULL;
+  std::bitset<128> bs6(num6);
+  VERIFY( bs6.to_ullong() == num6 );
+}
+
+int main()
+{
+  test01();
+  return 0;
+}