From winnings that require W-2Gs, I set aside one-third for taxes which I tuck away in the safe deposit box. When I return home, I deposit the funds into a special reserve account for taxes. I don't bother with win/loss statements because I don't trust their accuracy. I play with window markers everytime I go to Vegas. At the end of the year, I turn over the W-2G forms, marker statements, and cancelled checks to my accountant. If I have any taxable net winnings, I dip into the reserve account and pay the tax.