Record-Keeping Rules That Help You Survive a CRA Audit in Ontario

Most CRA audits are decided by paper, not by argument. A taxpayer with organized, complete records can usually resolve an audit with minor adjustments, if any. A taxpayer who can't produce supporting documentation is at the CRA's mercy — and can end up facing a reassessment, or even a net worth audit, simply because the records to prove otherwise don't exist.

Good CRA audit record-keeping isn't complicated, but it does require consistency. This guide covers what to keep, how long to keep it, and how to organize it so that if an audit letter arrives, you're not scrambling.

Why Records Matter More Than You Think

On an ordinary reassessment, the taxpayer generally bears the burden of showing the CRA's assessment is wrong. That means if you claimed a deduction and can't produce a receipt or supporting document years later, the CRA is often entitled to simply disallow it — regardless of whether the expense actually happened. Records aren't paperwork for its own sake; they're your evidence.

What Records to Keep

For Individuals

• Income slips (employment, investment, pension) and any income not reported on a slip
• Receipts for claimed deductions and credits (medical, charitable donations, childcare, moving expenses, tuition)
• Records supporting any capital gains or losses — purchase and sale documents for investments, property, and other capital assets
• Documentation for a principal residence sale, since it must be reported on Schedule 3 of your T1 even when the gain is fully sheltered by the Principal Residence Exemption
• Records of any support for non-taxable amounts you've received (gifts, inheritances, insurance proceeds) in case your finances are ever questioned

For Self-Employed Individuals and Businesses

• Sales records and invoices issued
• All expense receipts, organized by category
• Bank and credit card statements for every account used in the business
• Payroll records, including source deductions withheld and remitted
• GST/HST records — collected, remitted, and input tax credits claimed
• Vehicle logs, if claiming vehicle expenses
• Contracts, especially with anyone treated as an independent contractor rather than an employee

For Corporations

Everything above that applies to the business, plus:

• Minute books and corporate records
• Director and shareholder resolutions relevant to compensation, dividends, or loans
• Records supporting any related-party transactions (loans to or from shareholders, intercompany charges)

How Long to Keep Records

As a general rule, keep supporting records for at least as long as the CRA can reassess the related return under the normal reassessment rules, and longer where a transaction has ongoing tax consequences (such as the cost base of a property or investment you still hold, which you'll need when you eventually sell it). Because retention periods can vary by document type and circumstance, confirm the current CRA guidance for your specific situation before discarding anything, and when in doubt, keep records longer rather than shorter.

A useful discipline: don't destroy any record tied to an asset you still own. The purchase documents for a rental property, an investment, or shares in a business stay relevant for as long as you hold that asset, plus the retention period after you dispose of it.

Organizing Records So They're Actually Useful

Keeping records in a shoebox technically satisfies the letter of the rule but fails the spirit of it — if you can't retrieve what you need within an audit's timeline, disorganized records provide little practical protection.

• [ ] Separate business and personal accounts entirely — commingled funds are one of the most common audit red flags
• [ ] Reconcile bookkeeping against bank statements at least quarterly, not just at year-end
• [ ] Keep digital backups of paper receipts, since faded thermal paper receipts are a frequent problem in older audits
• [ ] File records by tax year and category so a specific document can be located quickly
• [ ] Retain contracts and agreements for the full life of the relationship, not just the year they were signed
• [ ] Document the business purpose of unusual or large transactions at the time they happen, not years later from memory

What Happens When Records Are Missing or Incomplete

If your records can't substantiate your reported income or claimed expenses, the CRA has options that are all worse for you than good bookkeeping would have been:

• Disallowing specific deductions or credits for lack of support
• Estimating income using indirect methods, including a net worth analysis that reconstructs income from your assets, debts, and spending
• In cases involving misrepresentation, potentially reassessing years otherwise closed under the normal reassessment period, and applying penalties

None of these outcomes require the CRA to prove you did anything deliberately wrong — inadequate records alone can be enough to trigger a less favourable reassessment.

Frequently asked questions