What records should I keep about my online gambling activity in case I am ever asked about it by Canadian tax authorities?

Good news first: for most Ottawa residents who play at Ontario-registered online casinos as a recreational pastime, lottery and certain other gambling winnings are non-taxable in Canada — unless you are in the business of gambling, in which case the proceeds and losses are considered for income tax purposes. The CRA's own guidance confirms this, and lottery winnings of any amount are explicitly listed among amounts that are not reported or taxed, unless the prize can be considered income from employment, a business, or property.

So why keep records at all? Because the question of whether you are a casual player or a "gambling business" is a judgment call, and large deposits flowing through your bank account from a casino can look unexplained to an auditor who doesn't know the source. The CRA's most common method of indirect income verification — the net worth method — has auditors examining changes in assets and liabilities, personal spending, and other information, including non-taxable sources of income such as lottery and gambling winnings. If you can't explain where the money came from, the CRA can draw its own conclusions.

What the CRA's own audit manual says it will ask for

If a taxpayer states that the source of funds is lottery or other winnings, the CRA will request records covering all winnings and losses. That's the key phrase: all winnings and losses, not just the big wins. The audit manual also notes that a taxpayer may often recall wins but have to be prompted to recall losses — which is exactly why contemporaneous records matter more than memory.

Online betting and gambling are specifically flagged in the audit manual, noting that they require the use of a credit card or e-commerce account where wagers are withdrawn and winnings are deposited, with payments ordinarily by credit card or money order. That paper trail already exists on the operator's side — but you want your own copy.

The records worth keeping

• Transaction history from the operator. Every Ontario-registered online casino maintains an account history. Download or screenshot your full deposit, withdrawal, and session history periodically — at least annually, ideally monthly for active players. This is your primary document.
• Bank and payment statements. Keep the statements that show deposits to and withdrawals from your casino account. These corroborate the operator records and show the money moving between your bank and the platform.
• A simple running log. A spreadsheet noting the date, platform, game type, amount deposited, and amount withdrawn for each session costs nothing to maintain and is far more convincing than reconstructed records assembled years later.
• Evidence that the site is Ontario-regulated. This one is easy: Ontario-registered operators display both the iGaming Ontario logo and the BetGuard logo on their site. A screenshot of the site footer showing those logos establishes you were playing on a regulated platform — relevant if you ever need to demonstrate the activity was lawful and above board.
• Proof of your net position, not just wins. The CRA is interested in the full picture. A record showing $20,000 in withdrawals alongside $18,500 in deposits tells a very different story than the withdrawals alone.

How long to keep them

Generally, taxpayers must keep books and records for six years. Using that as your benchmark for gambling records is sensible even though you are not filing them — it matches the standard window within which the CRA can reassess a return.

The "gambling business" exception — where it gets serious

Determining the commerciality of gambling can be challenging. Games of pure chance lack the badges of trade to which traditional tests of business activity can be applied. Traditional tests include evaluating a taxpayer's profit-making purpose and the commerciality of their activity. If you play systematically, use a defined strategy, treat it as a primary income source, or devote substantial time to it, a tax professional might advise you that your activity could be characterized differently. In that scenario, full business-style records — income, losses, expenses, time spent — become genuinely necessary. Talk to a qualified Canadian tax accountant if that description sounds like you; this is not a determination to make on your own.

For everyone else, the practical takeaway is simple: download your account statements from your Ontario-registered platform once or twice a year, keep the matching bank records, and file them somewhere you can find them. That modest habit protects you completely if a large withdrawal ever catches an auditor's eye. ConnexOntario (1-866-531-2600) is available if gambling ever feels like less of a pastime and more of a financial pressure point.