For the last 2.5 years I've been using the default MonoDevelop Web Reference in my MonoTouch applications for work, but it's come to the point where I really need and want to make use of the WCF features that I do in my Windows Phone applications. Even with the newly released iOS Integration in Visual Studio 2012, you still have to generate the proxy class with the slsvcutil included with the Silverlight 3.0 SDK. If you're like me, you probably don't have Version 3.0 of the Silverlight SDK, you can get it from Microsoft here. When running the tool you might get the following error: Error: An error occurred in the tool. Error: Could not load file or assembly 'C:\Program Files (x86)\Microsoft Silverl ight\5.1.10411.0\System.Runtime.Serialization.dll' or one of its dependencies. T his assembly is built by a runtime newer than the currently loaded runtime and c annot be loaded. Basically the tool is incorrectly trying to pull the newer 4.0 or 5.0 Silverlight Assemblies, to make it easy, I created a config file to simply drop into your c:\Program Files (x86)\Microsoft SDKs\Silverlight\v3.0\Tools folder, you can download it here. From a command line (remember the shortcut to hold shift down and right click in the folder to open a command prompt): [caption id="attachment_1853" align="aligncenter" width="593"]Silverlight 3 WCF Proxy Generation Silverlight 3 WCF Proxy Generation[/caption] Enter the following, assuming you want to create a proxy for a localhost WCF Service to your c:\tmp folder: SlSvcUtil.exe http://localhost/Service.svc?wsdl /noconfig /d:c:\tmp Though I should note, this will generate Array collections and not List or ObservableCollection collections. If you want to generate your Operation Contracts with return types of those collections simply add for List Collections: /collectionType:System.Collections.Generic.List`1 or ObservableCollection: /collectionType:System.Collections.ObjectModel.ObservableCollection`1