🇨🇦 Canada · 5 min read · Published 2026-09-07 · Updated 2026-09-07

Written by Jordan Reeves · Editorial review: automated source and figure checks (how we check this)

Sources last verified: 2026-09-07

Who Qualifies for the Disability Tax Credit?

Someone with a severe and prolonged impairment in physical or mental functions, certified by a medical practitioner on a prescribed form. The credit itself is modest; its real value is as the gateway to the Registered Disability Savings Plan and several other programs.

60-SECOND ANSWER

The disability tax credit is a modest non-refundable credit whose main value is unlocking the RDSP and related programs.

The answer:: Certification by a medical practitioner of a severe and prolonged impairment, approved by the Canada Revenue Agency.
The trap:: Not claiming it because the person has little taxable income. The credit transfers to a supporting spouse or parent.
The recommendation:: Ask for backdated approval when applying, because up to ten prior years can be reassessed.

Jump to the detail ↓

Where the AI summary above gets this wrong

"The disability tax credit is only worth claiming if you pay a lot of tax."

That's surface-true. Here's what it misses:

It transfers to a supporting relative — Where the person has insufficient income to use it, the credit can be transferred to a spouse, parent or other supporting individual.
It is a gateway, not just a credit — Approval is a precondition for opening a Registered Disability Savings Plan, and for several provincial and federal programs.
Approval can be backdated ten years — A successful application can be applied to prior returns, producing a refund for years already assessed.

→ See what a credit is worth at your rate

01 What qualifies

The test is a severe and prolonged impairment in physical or mental functions, meaning one expected to last at least twelve continuous months and markedly restricting a basic activity of daily living, or requiring life-sustaining therapy.

Certification is made by a medical practitioner on the prescribed form and is then assessed by the Canada Revenue Agency, which may accept, refuse, or approve for a limited number of years and require reapplication. The practitioner's fee for completing the form is itself a claimable medical expense.

Source: Disability tax credit (DTC)

02 Why the gateway matters more

As a credit it reduces tax by a moderate amount, and is unusable by someone with no taxable income. Its transferability to a supporting spouse, parent or grandparent addresses part of that.

The larger value is what approval unlocks. A Registered Disability Savings Plan cannot be opened without it, and that plan carries grants and bonds worth far more over time than the credit itself — the structure is in RDSP grants and bonds.

WORKED EXAMPLE · Try the numbers

Shows: what a given amount of additional taxable income costs you in tax at your marginal rate, and what you keep. Ignores: provincial surtaxes, credits that phase out with income, and any effect on income-tested benefits.

Amount ($)

Your marginal rate (%)

What you keep after tax

$6,700

At a 33% marginal rate, $10,000 costs $3,300 in tax and leaves $6,700.

Source: Disability tax credit (DTC)

03 The ten-year reassessment

Where the impairment existed in earlier years, an approved application can be applied retroactively to as many as ten prior tax years. Requesting that adjustment produces a refund of tax already paid in each of those years.

The request has to be made rather than assumed. Approval going forward does not automatically reopen prior returns, and families frequently discover years later that the retroactive claim was available and was never asked for.

A refused application is also worth appealing rather than abandoning. Refusals frequently turn on how the practitioner described the impairment rather than on the impairment itself, and a request for reconsideration supported by a fuller description from the same practitioner succeeds often enough to be the default response.

Source: Canadian income tax rates for individuals

The ten-year backdating is the largest unclaimed refund in the Canadian tax system. Families apply, get approved from the current year forward, and never learn that the same certificate could have reopened a decade of returns if someone had asked.