http://blogs.msdn.com/jpsanders/archive/2009/06/08/understanding-the-new-wininet-options-internet-suppress-cookie-persist-and-internet-suppress-cookie-persist-reset.aspxThese options are well documented. Important notes: These flags affect the process that you set this option from. You do not need to pass an InternetHandle (but no error if you do). Sample code: bool abRes = false ; DWORD adOption = INTERNET_SUPPRESS_COOKIE_PERSIST;en-USCommunityServer 2.1 SP1 (Build: 61025.2)