Ok, you need to use the API function "SendMessage" (i.e. SendMessageA). I suggest you download the API Guide (Do a search on API Guide on the Internet). The Scrollbar works by sending the WM_VSCROLL message. Now, you'll have to SubClass the Window you want to handle the Wheel Mouse on. You can do this by intercepting the WM_MOUSEWHELL Message. Again, all this is contained in the API Guide. If you need an example of SubClassing, I can help but I don't have a lot of time to explain it. Also, Subclassing is 100 times easier to do in .NET than VB6. After you have the WM_MOUSEWHEEL intercepted, just pass the message for it to scroll Up or Down by passing a "0" or "1" to the LParam of the SendMessage (it's either that or the WParam, can't remember off the top of my head). Call SendMessage(lstBoxHandle, WM_VSCROLL, 1, 0) Call SendMessage(lstBoxHandle, WM_VSCROLL, 0, 0) Not all those who are lost are looking to be found. But of those who are lost and those who are found, all are looking for something higher than themselves.