It goes on line 21 of Formextension software gambling BONUS ONLINE CASINO If tax is withheld from your gambling winnings, you will be sent a Form W2-G from the payer. Can I Deduct My Gambling Losses? You are allowed to list your annual gambling losses as an itemized deduction on Schedule A of your tax return. If you lost as much as, or more than, you won during the year. Gambling & Taxes (U.S. income tax). I'm a layperson, not a tax expert. That means you can never show a net loss for gambling. For example, if you lose $ playing slots, and then win a $.