diff --git a/include/boost/system/error_code.hpp b/include/boost/system/error_code.hpp
index 81c979b..70a41cd 100644
--- a/include/boost/system/error_code.hpp
+++ b/include/boost/system/error_code.hpp
@@ -607,8 +607,20 @@ namespace boost
       }
       else if( condition.category() == std::generic_category() || condition.category() == boost::system::generic_category() )
       {
-        return pc_->equivalent( code, boost::system::error_condition( condition.value(), boost::system::generic_category() ) );
+        boost::system::error_code bc( code, *pc_ );
+        boost::system::error_condition bn( condition.value(), boost::system::generic_category() );
+
+        return bc == bn;
       }
+#ifndef BOOST_NO_RTTI
+      else if( std_category const* pc2 = dynamic_cast< std_category const* >( &condition.category() ) )
+      {
+        boost::system::error_code bc( code, *pc_ );
+        boost::system::error_condition bn( condition.value(), *pc2->pc_ );
+
+        return bc == bn;
+      }
+#endif
       else
       {
         return false;
@@ -623,8 +635,7 @@ namespace boost
       }
       else if( *pc_ == boost::system::generic_category() )
       {
-        std::error_category const & st = std::generic_category();
-        return st.equivalent( code, condition );
+        return code == std::error_condition( condition, std::generic_category() );
       }
       else
       {
@@ -644,5 +655,3 @@ namespace boost
 # endif
 
 #endif // BOOST_SYSTEM_ERROR_CODE_HPP
-
-
diff --git a/test/std_interop_test.cpp b/test/std_interop_test.cpp
index 5ee69a8..6b9c77d 100644
--- a/test/std_interop_test.cpp
+++ b/test/std_interop_test.cpp
@@ -120,6 +120,8 @@ static void test_system_category()
     }
 }
 
+// test_user_category
+
 class user_category_impl: public boost::system::error_category
 {
 public:
@@ -251,11 +253,103 @@ static void test_user_category()
     }
 }
 
+// test_user2_category
+
+enum user2_errc
+{
+    my_enoent = 1,
+    my_einval,
+    my_other
+};
+
+class user2_category_impl: public boost::system::error_category
+{
+public:
+
+    virtual const char * name() const BOOST_NOEXCEPT
+    {
+        return "user2";
+    }
+
+    virtual std::string message( int ev ) const
+    {
+        char buffer[ 256 ];
+        sprintf( buffer, "user2 message %d", ev );
+
+        return buffer;
+    }
+
+    virtual boost::system::error_condition default_error_condition( int ev ) const BOOST_NOEXCEPT
+    {
+        return boost::system::error_condition( ev, *this );
+    }
+
+    virtual bool equivalent( int code, const boost::system::error_condition & condition ) const BOOST_NOEXCEPT
+    {
+        return default_error_condition( code ) == condition;
+    }
+
+    virtual bool equivalent( const boost::system::error_code & code, int condition ) const BOOST_NOEXCEPT
+    {
+        if( code.category() == *this )
+        {
+            return condition == code.value();
+        }
+        else if( condition == my_enoent )
+        {
+            return code == boost::system::errc::no_such_file_or_directory;
+        }
+        else if( condition == my_einval )
+        {
+            return code == boost::system::errc::invalid_argument;
+        }
+        else
+        {
+            return false;
+        }
+    }
+};
+
+boost::system::error_category const & user2_category()
+{
+    static user2_category_impl cat_;
+    return cat_;
+}
+
+static void test_user2_category()
+{
+    boost::system::error_category const & bt = user2_category();
+    std::error_category const & st = bt;
+
+    int ev = my_enoent;
+
+    boost::system::error_condition bn( ev, bt );
+
+    BOOST_TEST_EQ( bn.value(), ev );
+    BOOST_TEST_EQ( &bn.category(), &bt );
+
+    boost::system::error_code bc = make_error_code( boost::system::errc::no_such_file_or_directory );
+
+    BOOST_TEST( bc == bn );
+
+    std::error_condition sn( bn );
+
+    BOOST_TEST_EQ( sn.value(), ev );
+    BOOST_TEST_EQ( &sn.category(), &st );
+
+    std::error_code sc( bc );
+
+    BOOST_TEST( sc == sn );
+}
+
+//
+
 int main()
 {
     test_generic_category();
     test_system_category();
     test_user_category();
+    test_user2_category();
 
     return boost::report_errors();
 }