Fill Out Form ISP-3520 Online
Request for Voluntary Federal Income Tax Deductions - CPP/OAS
Employment and Social Development Canada
Requests voluntary federal income tax withholding from Canada Pension Plan or Old Age Security payments.
Reviewed July 2026
How it works
- 1
Open the form. The official PDF loads straight into the editor, no download needed first.
- 2
Fill it out in the editor. Click anywhere to type, add checkmarks and place your signature.
- 3
Download your PDF. Save the completed form, ready to print or submit.
Form ISP-3520 is the Request for Voluntary Federal Income Tax Deductions from Canada Pension Plan and Old Age Security payments. CPP and OAS are taxable, but tax is not withheld from them automatically. This short form tells Service Canada how much federal income tax to deduct from each monthly payment so you are not left with a large balance owing when you file your return.
You can complete ISP-3520 in the Universal PDF editor. Choose your deduction, fill in your details on screen, then download the finished PDF to print, sign, and send to Service Canada.
What is Form ISP-3520 used for
The form starts, changes, or stops voluntary federal income tax withholding on your CPP or OAS benefits. You choose either a percentage of your monthly payment or a fixed monthly sum, and Service Canada deducts it at source and remits it to the Canada Revenue Agency on your behalf.
Voluntary deductions are a budgeting tool. They spread your tax bill across the year instead of leaving it all for tax time, and they can reduce or replace quarterly instalment payments that the CRA might otherwise require.
Who applies with Form ISP-3520
Anyone receiving CPP benefits, OAS benefits, or both can file the form. It is commonly used by new retirees who discover their first year of benefits created a tax bill, by people with several income sources whose combined income pushes them into instalments, and by anyone who simply prefers tax to come off before the payment arrives.
Non-residents of Canada normally should not use this form, because their CPP and OAS payments are subject to non-resident withholding under different rules. The CRA explains the non-resident treatment on canada.ca.
How to fill out Form ISP-3520
The form takes only a few minutes:
- Enter your Social Insurance Number, name, address, and telephone number.
- Indicate which benefit the deduction applies to, CPP, OAS, or both.
- Choose the deduction as either a percentage of your monthly payment or a set monthly sum.
- To change an existing deduction, enter the new choice; to cancel one, indicate that deductions should stop.
- Sign and date the request.
How to submit it
Mail the signed form to the Service Canada office for your province or territory, using the addresses on canada.ca, or drop it off at a Service Canada office. You can also set up or change voluntary tax deductions online through My Service Canada Account without using the paper form. The new deduction takes effect once Service Canada processes the request, so allow time before the next payment cycle.
Frequently asked questions
No. Both benefits are taxable, but nothing is withheld unless you request it with this form or through My Service Canada Account, or you are a non-resident subject to mandatory withholding.
That depends on your total income and tax bracket. Reviewing last year's return or asking a tax preparer gives a reasonable starting point, and you can adjust the deduction at any time with a new request.
Yes. Submit a new ISP-3520 or update your choice in My Service Canada Account whenever your situation changes. The latest request replaces the previous one.
The deduction is federal income tax withheld at source. When you file your return, the amounts withheld are credited against your total federal and provincial tax payable, since the CRA administers both through one return in most provinces.
Generally no. Non-residents have tax withheld from CPP and OAS under non-resident rules, which depend on your country of residence and any tax treaty. See the CRA's non-resident guidance on canada.ca.
Related forms
Universal PDF is an independent product and is not affiliated with or endorsed by any government agency. Forms are provided from official government sources; always confirm you have the current version before filing.
This form is reproduced from official Canadian government sources. Universal PDF is not affiliated with or endorsed by any Canadian federal or provincial government body; always confirm you have the current version on the official site.