diff --git a/.gitignore b/.gitignore
index b39017b2..45b7161c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,3 +6,10 @@ ruby/Makefile
*.6
_obj
_test
+/csharp/msgpack.suo
+/csharp/msgpack/bin
+/csharp/msgpack/obj
+/csharp/msgpack/msgpack.csproj.user
+/csharp/msgpack.tests/obj
+/csharp/msgpack.tests/bin
+/csharp/msgpack.tests/msgpack.tests.csproj.user
diff --git a/csharp/msgpack.sln b/csharp/msgpack.sln
new file mode 100644
index 00000000..351c7b8a
--- /dev/null
+++ b/csharp/msgpack.sln
@@ -0,0 +1,26 @@
+
+Microsoft Visual Studio Solution File, Format Version 11.00
+# Visual Studio 2010
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "msgpack", "msgpack\msgpack.csproj", "{E1809531-EC2A-4EA6-B0E8-CC815EDFAA2F}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "msgpack.tests", "msgpack.tests\msgpack.tests.csproj", "{CE24167B-8F0A-4670-BD1E-3C283311E86B}"
+EndProject
+Global
+ GlobalSection(SolutionConfigurationPlatforms) = preSolution
+ Debug|Any CPU = Debug|Any CPU
+ Release|Any CPU = Release|Any CPU
+ EndGlobalSection
+ GlobalSection(ProjectConfigurationPlatforms) = postSolution
+ {E1809531-EC2A-4EA6-B0E8-CC815EDFAA2F}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+ {E1809531-EC2A-4EA6-B0E8-CC815EDFAA2F}.Debug|Any CPU.Build.0 = Debug|Any CPU
+ {E1809531-EC2A-4EA6-B0E8-CC815EDFAA2F}.Release|Any CPU.ActiveCfg = Release|Any CPU
+ {E1809531-EC2A-4EA6-B0E8-CC815EDFAA2F}.Release|Any CPU.Build.0 = Release|Any CPU
+ {CE24167B-8F0A-4670-BD1E-3C283311E86B}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+ {CE24167B-8F0A-4670-BD1E-3C283311E86B}.Debug|Any CPU.Build.0 = Debug|Any CPU
+ {CE24167B-8F0A-4670-BD1E-3C283311E86B}.Release|Any CPU.ActiveCfg = Release|Any CPU
+ {CE24167B-8F0A-4670-BD1E-3C283311E86B}.Release|Any CPU.Build.0 = Release|Any CPU
+ EndGlobalSection
+ GlobalSection(SolutionProperties) = preSolution
+ HideSolutionNode = FALSE
+ EndGlobalSection
+EndGlobal
diff --git a/csharp/msgpack.tests/AssemblyInfo.cs b/csharp/msgpack.tests/AssemblyInfo.cs
new file mode 100644
index 00000000..de7e181e
--- /dev/null
+++ b/csharp/msgpack.tests/AssemblyInfo.cs
@@ -0,0 +1,36 @@
+using System.Reflection;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+// General Information about an assembly is controlled through the following
+// set of attributes. Change these attribute values to modify the information
+// associated with an assembly.
+[assembly: AssemblyTitle ("msgpack.tests")]
+[assembly: AssemblyDescription ("")]
+[assembly: AssemblyConfiguration ("")]
+[assembly: AssemblyCompany ("Microsoft")]
+[assembly: AssemblyProduct ("msgpack.tests")]
+[assembly: AssemblyCopyright ("Copyright © Microsoft 2011")]
+[assembly: AssemblyTrademark ("")]
+[assembly: AssemblyCulture ("")]
+
+// Setting ComVisible to false makes the types in this assembly not visible
+// to COM components. If you need to access a type in this assembly from
+// COM, set the ComVisible attribute to true on that type.
+[assembly: ComVisible (false)]
+
+// The following GUID is for the ID of the typelib if this project is exposed to COM
+[assembly: Guid ("82a4db7c-686b-4206-9cc9-9aae082d7e73")]
+
+// Version information for an assembly consists of the following four values:
+//
+// Major Version
+// Minor Version
+// Build Number
+// Revision
+//
+// You can specify all the values or you can default the Build and Revision Numbers
+// by using the '*' as shown below:
+// [assembly: AssemblyVersion("1.0.*")]
+[assembly: AssemblyVersion ("1.0.0.0")]
+[assembly: AssemblyFileVersion ("1.0.0.0")]
diff --git a/csharp/msgpack.tests/msgpack.tests.csproj b/csharp/msgpack.tests/msgpack.tests.csproj
new file mode 100644
index 00000000..381bf668
--- /dev/null
+++ b/csharp/msgpack.tests/msgpack.tests.csproj
@@ -0,0 +1,62 @@
+
+
+
+ Debug
+ AnyCPU
+ 8.0.30703
+ 2.0
+ {CE24167B-8F0A-4670-BD1E-3C283311E86B}
+ Library
+ Properties
+ msgpack.tests
+ msgpack.tests
+ v4.0
+ 512
+
+
+ true
+ full
+ false
+ bin\Debug\
+ DEBUG;TRACE
+ prompt
+ 4
+
+
+ pdbonly
+ true
+ bin\Release\
+ TRACE
+ prompt
+ 4
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+ {E1809531-EC2A-4EA6-B0E8-CC815EDFAA2F}
+ msgpack
+
+
+
+
+
\ No newline at end of file
diff --git a/csharp/msgpack/AssemblyInfo.cs b/csharp/msgpack/AssemblyInfo.cs
new file mode 100644
index 00000000..0ef2ef9b
--- /dev/null
+++ b/csharp/msgpack/AssemblyInfo.cs
@@ -0,0 +1,36 @@
+using System.Reflection;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+// General Information about an assembly is controlled through the following
+// set of attributes. Change these attribute values to modify the information
+// associated with an assembly.
+[assembly: AssemblyTitle ("msgpack")]
+[assembly: AssemblyDescription ("")]
+[assembly: AssemblyConfiguration ("")]
+[assembly: AssemblyCompany ("Microsoft")]
+[assembly: AssemblyProduct ("msgpack")]
+[assembly: AssemblyCopyright ("Copyright © Microsoft 2011")]
+[assembly: AssemblyTrademark ("")]
+[assembly: AssemblyCulture ("")]
+
+// Setting ComVisible to false makes the types in this assembly not visible
+// to COM components. If you need to access a type in this assembly from
+// COM, set the ComVisible attribute to true on that type.
+[assembly: ComVisible (false)]
+
+// The following GUID is for the ID of the typelib if this project is exposed to COM
+[assembly: Guid ("aae99974-7a7d-4787-83ca-614779d54bd2")]
+
+// Version information for an assembly consists of the following four values:
+//
+// Major Version
+// Minor Version
+// Build Number
+// Revision
+//
+// You can specify all the values or you can default the Build and Revision Numbers
+// by using the '*' as shown below:
+// [assembly: AssemblyVersion("1.0.*")]
+[assembly: AssemblyVersion ("1.0.0.0")]
+[assembly: AssemblyFileVersion ("1.0.0.0")]
diff --git a/csharp/msgpack/BoxingPacker.cs b/csharp/msgpack/BoxingPacker.cs
new file mode 100644
index 00000000..c513a309
--- /dev/null
+++ b/csharp/msgpack/BoxingPacker.cs
@@ -0,0 +1,148 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.IO;
+using System.Reflection;
+
+namespace msgpack
+{
+ public class BoxingPacker
+ {
+ static Type KeyValuePairDefinitionType;
+
+ static BoxingPacker ()
+ {
+ KeyValuePairDefinitionType = typeof (KeyValuePair