At a glance

If CRA approves your Disability Tax Credit (DTC) for earlier years, you may be able to revise past tax returns and recover income tax you overpaid. The first thing to check is the date range on the DTC notice—not the date when you first applied.

The DTC is a non-refundable credit. A retroactive approval can produce a refund only to the extent eligible tax was paid or another qualifying family member can use a transferable unused amount.

Check exactly which years CRA approved

Suppose you apply in September 2026 and CRA approves DTC eligibility from 2022 to 2026. The medically approved years are 2022–2026, even though the decision arrives in 2026.

This does not mean that every tax year in that range yields the same refund. Your income, federal and provincial tax owed, other credits, and prior claims all affect the result.

Understand the 10-year adjustment window

CRA can generally consider eligible prior-year claims going back up to 10 calendar years under its taxpayer relief rules. The year of medical eligibility and the period in which a tax return can still be adjusted are two separate limits.

Example: approval reaches back to 2012, but a request made in 2026 would not necessarily permit reassessments for every early year. Check CRA's adjustment window for the year you submit the request.

How to change your prior returns

Use CRA's Change My Return service, ReFILE where applicable, or an adjustment request. Some DTC applications allow applicants to request automatic changes for previous years. Review what CRA actually adjusted before submitting duplicates.

For each eligible tax year, check the person's income tax owing first, then whether a spouse, parent or other supporting relative qualifies for a transfer of unused disability amount. The correct claim is made on the corresponding year's tax return using that year's rates and rules.

Example: why approved years don't equal automatic refunds

Leo was approved for 2023, 2024, 2025 and 2026. His 2023 tax payable was already zero after other credits. Adding another non-refundable credit cannot reduce that tax below zero.

For 2024 and 2025 he paid income tax, so adjustments could reduce that tax and generate refunds. If his spouse supports him and meets the transfer requirements, they should review whether any unused amount is transferable.

Keep records and review future benefits

Save the approval letter, amended assessments and calculations. DTC approval can also affect eligibility for other programs, but each has separate eligibility and application rules.