There is a Micosoft System Journal article that talks about this very thing. I tried the example code and it worked. I also wrote a few DLL with Visual C++ (following the steps in the article) and they worked fine with Visual Basic. You can find the article at: http://www.asia.microsoft.com/msj/defaulttop.asp?page=/msj/0498/inthisissuefeatures0498.htm gl Jonathan Craig

Give the button the TBSTYLE_CHECK style. (Note - that constant was renamed to BTNS_CHECK in SDKs that shipped after VC 6.)