Yes, you can use COM components regardless of what technology was used to build them. There are several ways to do this. The best way is to use a Windows XP feature called registry free COM. This feature allows COM objects to be deployed with your “ClickOnce” application & be used by that application without requiring the COM object to be registered globally. Visual Studio natively supports publishing applications that use registry free COM. This feature only works on Windows XP & newer client OSes. The 2nd option is to deploy the COM object as a static file in your “ClickOnce” deployment & invoke the COM object entry points directly (instead of going through COM itself). This works on all OSes, but is considerably more complicated. The 3rd option is to deploy your COM object with the bootstrapper. The major limitation there is that “ClickOnce” can no auto-update bootstrapper installed components.