diff --git a/Facepunch.Steamworks.Test/Client.cs b/Facepunch.Steamworks.Test/Client.cs
index a6ca188..796f2ae 100644
--- a/Facepunch.Steamworks.Test/Client.cs
+++ b/Facepunch.Steamworks.Test/Client.cs
@@ -131,5 +131,49 @@ public void GetServers()
                 Console.WriteLine( "Unresponsive: " + query.Unresponsive.Count.ToString() );
             }
         }
+
+        [TestMethod]
+        public void InventoryDefinitions()
+        {
+            using ( var client = new Facepunch.Steamworks.Client( 252490 ) )
+            {
+                Assert.IsNotNull( client.Inventory.Definitions );
+                Assert.AreNotEqual( 0, client.Inventory.Definitions.Length );
+            }
+        }
+
+        [TestMethod]
+        public void InventoryItemList()
+        {
+            using ( var client = new Facepunch.Steamworks.Client( 252490 ) )
+            {
+                bool CallbackCalled = false;
+
+                // OnUpdate hsould be called when we receive a list of our items
+                client.Inventory.OnUpdate = () => { CallbackCalled = true; };
+
+                // tell steam to download the items
+                client.Inventory.Refresh();
+
+                // Wait for the items
+                while ( client.Inventory.Items == null )
+                {
+                    client.Update();
+                    System.Threading.Thread.Sleep( 10 );
+                }
+
+                // make sure callback was called
+                Assert.IsTrue( CallbackCalled );
+
+                // Make sure items are valid
+                foreach ( var item in client.Inventory.Items )
+                {
+                    Assert.IsNotNull( item );
+                    Assert.IsNotNull( item.Definition );
+
+                    Console.WriteLine( item.Definition.Name + " - " + item.Id );
+                }
+            }
+        }
     }
 }
diff --git a/Facepunch.Steamworks/Client.cs b/Facepunch.Steamworks/Client.cs
index 6404ee3..2cbfac0 100644
--- a/Facepunch.Steamworks/Client.cs
+++ b/Facepunch.Steamworks/Client.cs
@@ -14,6 +14,7 @@ public partial class Client : IDisposable
         internal Valve.Steamworks.ISteamUser _user;
         internal Valve.Steamworks.ISteamFriends _friends;
         internal Valve.Steamworks.ISteamMatchmakingServers _servers;
+        internal Valve.Steamworks.ISteamInventory _inventory;
 
         /// <summary>
         /// Current running program's AppId
@@ -60,6 +61,7 @@ public Client( uint appId )
             _friends = _client.GetISteamFriends( _huser, _hpipe, "SteamFriends015" );
             _user = _client.GetISteamUser( _huser, _hpipe, "SteamUser019" );
             _servers = _client.GetISteamMatchmakingServers( _huser, _hpipe, "SteamMatchMakingServers002" );
+            _inventory = _client.GetISteamInventory( _huser, _hpipe, "STEAMINVENTORY_INTERFACE_V001" );
 
             AppId = appId;
             Username = _friends.GetPersonaName();
@@ -103,11 +105,20 @@ public void Update()
         {
             Valve.Steamworks.SteamAPI.RunCallbacks();
             Voice.Update();
+            Inventory.Update();
         }
 
         public bool Valid
         {
             get { return _client != null; }
         }
+
+        internal Action InstallCallback<T>( int type, Action<T> action )
+        {
+            var ptr = Marshal.GetFunctionPointerForDelegate( action );
+            Valve.Steamworks.SteamAPI.RegisterCallback( ptr, type );
+
+            return () => Valve.Steamworks.SteamAPI.UnregisterCallback( ptr );
+        }
     }
 }
diff --git a/Facepunch.Steamworks/Client/Inventory.cs b/Facepunch.Steamworks/Client/Inventory.cs
new file mode 100644
index 0000000..b097f57
--- /dev/null
+++ b/Facepunch.Steamworks/Client/Inventory.cs
@@ -0,0 +1,221 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace Facepunch.Steamworks
+{
+    public partial class Client : IDisposable
+    {
+        Inventory _inv;
+
+        public Inventory Inventory
+        {
+            get
+            {
+                if ( _inv == null )
+                    _inv = new Inventory( this );
+
+                return _inv;
+            }
+        }
+    }
+
+    public class Inventory
+    {
+        /// <summary>
+        /// Called when the items are first retrieved, and when they change
+        /// </summary>
+        public Action OnUpdate;
+
+        internal Client client;
+        private int updateRequest = 0;
+
+        internal Inventory( Client c )
+        {
+            client = c;
+
+            LoadItemDefinitions();
+
+
+        }
+
+        /// <summary>
+        /// Call this to retrieve the items.
+        /// Note that if this has already been called it won't
+        /// trigger a call to OnUpdate unless the items have changed
+        /// </summary>
+        public void Refresh()
+        {
+            // Pending
+            if ( updateRequest != 0 )
+                return;
+
+            client._inventory.GetAllItems( ref updateRequest );
+        }
+
+        internal void LoadItemDefinitions()
+        {
+            //
+            // Make sure item definitions are loaded, because we're going to be using them.
+            //
+            client._inventory.LoadItemDefinitions();
+
+            int[] ids;
+            if ( !client._inventory.GetItemDefinitionIDs( out ids ) )
+                return;
+
+            Definitions = ids.Select( x =>
+            {
+                var d = new Definition()
+                {
+                    client = client,
+                    Id = x
+                };
+
+                d.SetupCommonProperties();
+                return d;
+
+            } ).ToArray(); 
+        }
+
+        internal T DefinitionProperty<T>( int i, string name )
+        {
+            string val = string.Empty;
+            client._inventory.GetItemDefinitionProperty( i, name, out val );
+            return (T) Convert.ChangeType( val, typeof( T) );
+        }
+
+        internal void DestroyResult()
+        {
+            if ( updateRequest != 0 )
+            {
+                client._inventory.DestroyResult( updateRequest );
+                updateRequest = 0;
+            }
+        }
+
+
+        internal void Update()
+        {
+            UpdateRequest();
+        }
+
+        private void UpdateRequest()
+        {
+            if ( updateRequest == 0 )
+                return;
+
+            var status = (Valve.Steamworks.EResult) client._inventory.GetResultStatus( updateRequest );
+
+            if ( status == Valve.Steamworks.EResult.k_EResultPending )
+                return;
+
+            if ( status == Valve.Steamworks.EResult.k_EResultOK || status == Valve.Steamworks.EResult.k_EResultExpired )
+            {
+                RetrieveInventory();
+            }
+
+            // Some other error
+            // Lets just retry.
+            DestroyResult();
+            Refresh();
+        }
+
+        /// <summary>
+        /// A list of items owned by this user. You should call Refresh() before trying to access this, 
+        /// and then wait until it's non null or listen to OnUpdate to find out immediately when it's populated.
+        /// </summary>
+        public Item[] Items;
+
+        private void RetrieveInventory()
+        {
+            Valve.Steamworks.SteamItemDetails_t[] items = null;
+            client._inventory.GetResultItems( updateRequest, out items );
+
+            Items = items.Select( x =>
+            {
+                return new Item()
+                {
+                    client          = client,
+                    Quantity        = x.m_unQuantity,
+                    Id              = x.m_itemId,
+                    DefinitionId    = x.m_iDefinition,
+                    TradeLocked     = ( (int)x.m_unFlags & (int)Valve.Steamworks.ESteamItemFlags.k_ESteamItemNoTrade ) != 0,
+                    Definition      = Definitions.FirstOrDefault( y => y.Id == x.m_iDefinition )
+                };
+            } ).ToArray();
+
+            //
+            // Tell everyone we've got new items!
+            //
+            OnUpdate?.Invoke();
+        }
+
+        /// <summary>
+        /// An item in your inventory.
+        /// </summary>
+        public class Item
+        {
+            internal Client client;
+
+            public ulong Id;
+            public int Quantity;
+
+            public int DefinitionId;
+            public Definition Definition;
+
+            public bool TradeLocked;
+        }
+
+        /// <summary>
+        /// A list of items defined for this app. 
+        /// This should be immediately populated and available.
+        /// </summary>
+        public Definition[] Definitions;
+
+
+        /// <summary>
+        /// An item definition. This describes an item in your Steam inventory, but is
+        /// not unique to that item. For example, this might be a tshirt, but you might be able to own
+        /// multiple tshirts.
+        /// </summary>
+        public class Definition
+        {
+            internal Client client;
+
+            public int Id;
+            public string Name;
+            public string Description;
+
+            public DateTime Created;
+            public DateTime Modified;
+
+            public T GetProperty<T>( string name )
+            {
+                string val = string.Empty;
+
+                if ( !client._inventory.GetItemDefinitionProperty( Id, name, out val ) )
+                    return default( T );
+
+                try
+                {
+                    return (T)Convert.ChangeType( val, typeof( T ) );
+                }
+                catch( System.Exception )
+                {
+                    return default( T );
+                }
+            }
+
+        internal void SetupCommonProperties()
+        {
+            Name = GetProperty<string>( "name" );
+            Description = GetProperty<string>( "description" );
+            Created = GetProperty<DateTime>( "timestamp" );
+            Modified = GetProperty<DateTime>( "modified" );
+        }
+    }
+
+    }
+}
diff --git a/Facepunch.Steamworks/Facepunch.Steamworks.csproj b/Facepunch.Steamworks/Facepunch.Steamworks.csproj
index bcf343e..510a2a1 100644
--- a/Facepunch.Steamworks/Facepunch.Steamworks.csproj
+++ b/Facepunch.Steamworks/Facepunch.Steamworks.csproj
@@ -119,6 +119,7 @@
     <Compile Include="Client.Voice.cs" />
     <Compile Include="Client.Auth.cs" />
     <Compile Include="Client.cs" />
+    <Compile Include="Client\Inventory.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="steam_api_interop.cs" />
   </ItemGroup>
diff --git a/Facepunch.Steamworks/steam_api_interop.cs b/Facepunch.Steamworks/steam_api_interop.cs
index 76d6a83..bbd205b 100644
--- a/Facepunch.Steamworks/steam_api_interop.cs
+++ b/Facepunch.Steamworks/steam_api_interop.cs
@@ -2558,7 +2558,7 @@ internal override ISteamInventory GetISteamInventory( uint hSteamuser, uint hSte
         {
             CheckIfUsable();
             IntPtr result = NativeEntrypoints.SteamAPI_ISteamClient_GetISteamInventory(m_pSteamClient,hSteamuser,hSteamPipe,pchVersion);
-            return (ISteamInventory)Marshal.PtrToStructure( result, typeof( ISteamInventory ) );
+            return new CSteamInventory( result );
         }
         internal override ISteamVideo GetISteamVideo( uint hSteamuser, uint hSteamPipe, string pchVersion )
         {