In your setup project, make sure you selected the option to add an assembly and not the option to add a file. After you add the assembly, select it in the view pane and open the Properties dialog. The "Register" property should have a drop down list of the available registration options for the assembly. By default, .net assemblies are not set up to register – see http://msdn2.microsoft.com/en-us/library/z5s1e2wh(VS.90).aspx. Change the setting from DoNotRegister to COM.