In .NET 2.0 you can you use dll.config files. But once you try to use these dll's in other applications, it is not possible to read the settings in these files. You need to merge the dl.config with the application configuration file to be able to read these settings. To merge the configuration files, copy all the content in the dll.config file and put it in the application config file. Then the dll will be able to read them again!