If you spend time gambling and sometimes win but often lose, you might wonder whether the IRS lets you write off those losses. The IRS requires you to report all gambling winnings as income, so it does allow you to deduct gambling losses, but only up to the amount of your winnings. You cannot deduct more in losses than you won, and you cannot use gambling losses to create or increase a tax loss. To claim gambling losses, you must itemize your deductions rather than take the standard deduction. Keeping a detailed log of your wins and losses throughout the year is important because the IRS may ask for documentation.