This should provide the necessary detail and comfort level Directly off the IRS website: It is important to keep an accurate diary or similar record of your gambling winnings and losses. To deduct your losses, you must be able to provide receipts, tickets, statements or other records that show the amount of both your winnings and losses. Refer to Publication 529, Miscellaneous Deductions, for more information. Diary of winnings and losses. You must keep an accurate diary or similar record of your losses and winnings. Your diary should contain at least the following information. The date and type of your specific wager or wagering activity. The name and address or location of the gambling establishment. The names of other persons present with you at the gambling establishment. The amount(s) you won or lost. Proof of winnings and losses. In addition to your diary, you should also have other documentation. You can generally prove your winnings and losses through Form W-2G, Certain Gambling Winnings, Form 5754, Statement by Person(s) Receiving Gambling Winnings, wagering tickets, canceled checks, substitute checks, credit records, bank withdrawals, and statements of actual winnings or payment slips provided to you by the gambling establishment. For specific wagering transactions, you can use the following items to support your winnings and losses. These recordkeeping suggestions are intended as general guidelines to help you establish your winnings and losses. They are not all-inclusive. Your tax liability depends on your particular facts and circumstances. Keno. Copies of the keno tickets you purchased that were validated by the gambling establishment, copies of your casino credit records, and copies of your casino check cashing records. Slot machines. A record of the machine number and all winnings by date and time the machine was played. Table games (twenty-one (blackjack), craps, poker, baccarat, roulette, wheel of fortune, etc.). The number of the table at which you were playing. Casino credit card data indicating whether the credit was issued in the pit or at the cashier's cage. Bingo. A record of the number of games played, cost of tickets purchased, and amounts collected on winning tickets. Supplemental records include any receipts from the casino, parlor, etc. Racing (horse, harness, dog, etc.). A record of the races, amounts of wagers, amounts collected on winning tickets, and amounts lost on losing tickets. Supplemental records include unredeemed tickets and payment records from the racetrack. Lotteries. A record of ticket purchases, dates, winnings, and losses. Supplemental records include unredeemed tickets, payment slips, and winnings statements.