How to change your return

Do not file another return for that year.

Wait until you receive your notice of assessment before asking for changes to your return.

Generally you can only request a change to a return for a tax year ending in any of the 10 previous calendar years. For example, a request made in 2017 must relate to the 2007 or a later tax year to be considered.


Log on to My Account and click Change my return.

You cannot use Change my return

  • to change:
    • a tax return that has not been assessed
    • a tax return where nine reassessments exist for a particular tax year
    • a bankruptcy return
    • a return prior to the year of bankruptcy
    • carryback amounts such as capital or non-capital losses
    • a return of an international or non-resident client (including deemed residents of Canada, newcomers to Canada, and individuals who left Canada during the year)
    • the elected split-pension amount
    • a return where you have income from a business with a permanent establishment outside your province or territory of residence (you have to complete Form T2203, Provincial and Territorial Taxes - Multiple Jurisdictions)

In any of these cases, go to “By mail” below.


If you are an EFILE service provider, you can change your client’s tax return for the 2015 and 2016 tax years by using the ReFILE service with your certified EFILE software.

By mail

Send both of the following to your tax centre:

  • a completed Form T1-ADJ, T1 Adjustment Request, or a signed letter giving details of your request (including the years of the returns to be changed), your social insurance number, your address, and a telephone number where we can call you during the day
  • all supporting documents for the change, including those for the original assessment, unless you have already sent them to us

Send your current year return separately from any request to change a return for another year.

Processing times

Important notice

Due to higher than usual inventory levels, there may be a delay in processing your T1 Adjustment request. We are actively addressing the delay and appreciate your patience as we strive to return to our usual service standards.

  • online, usually within 2 weeks
  • by mail, usually within 8 weeks 

It may take longer if:  

  • Your request is sent in spring or early summer
  • Your request needs more review
  • We have to contact you or your authorized representative for more information or documentation

When our review is done we will send you:

  • a notice of reassessment showing any changes to your return and
  • a letter explaining why we did not make the changes you asked for or if no changes were needed

To change your address, go to How to change your address.

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