How to Write an Affidavit for Canadian Courts (2026 Guide)

An affidavit is one of the most important documents you will prepare for court. It is your sworn evidence — your opportunity to tell the court what happened, in your own words, under oath. Getting it right matters.

This guide covers how to write, format, and swear an affidavit for Canadian courts.

Important disclaimer: This article is for general informational purposes only and does not constitute legal advice. Court rules vary by province and court level. For advice specific to your situation, consult a licensed lawyer or paralegal.

What Is an Affidavit?

An affidavit is a written statement of facts that you sign and swear (or affirm) to be true. Once sworn, it has the same legal weight as testimony given in person in court. If you knowingly include false information in an affidavit, you may be charged with perjury, which is a criminal offence under section 131 of the Criminal Code.

Courts rely on affidavits in many situations, including:

Motions and applications — most interlocutory proceedings use affidavit evidence rather than live testimony
Family court proceedings — financial statements, custody applications, and support variations
Small Claims Court — some courts accept affidavit evidence at trial or for default judgment applications
Administrative tribunals — landlord-tenant boards, human rights tribunals, and other bodies

When Do Courts Require Affidavits?

You will likely need an affidavit when:

You are bringing or responding to a motion (an interim application to the court)
You are filing an application (a proceeding started by a Notice of Application rather than a Statement of Claim)
You need to prove service of documents (Affidavit of Service)
You are providing financial disclosure in family law proceedings
You are applying for default judgment
A tribunal requires written evidence in support of your application

Structure of an Affidavit

While the exact format varies by province and court level, most Canadian affidavits follow this general structure:

1. The Title (Caption)

The top of the affidavit identifies:

The court (e.g., Ontario Superior Court of Justice)
The court file number
The parties (plaintiff/defendant or applicant/respondent)
The title of the document (e.g., "Affidavit of Jane Smith")

2. The Introduction

The first paragraph identifies who you are and states that you are swearing or affirming the affidavit. Example:

"I, Jane Smith, of the City of Toronto, in the Province of Ontario, MAKE OATH AND SAY (or AFFIRM):"

3. The Body (Numbered Paragraphs)

The body of the affidavit contains your evidence, presented in numbered paragraphs. Each paragraph should address a single fact or topic.

Key principles:

First-hand knowledge: State only what you personally saw, did, heard, or experienced. Statements about what someone else told you are generally hearsay and may be inadmissible or given less weight.
Chronological order: Present facts in the order they happened.
Be specific: Include dates, times, amounts, and names. "In or about March 2025" is acceptable if you cannot recall the exact date, but be as precise as possible.
Factual, not argumentative: State facts, not opinions or legal conclusions. "The defendant failed to pay" is a fact. "The defendant's behaviour was outrageous and unconscionable" is argument.

4. References to Exhibits

If you are attaching documents (contracts, emails, photos, invoices), refer to them in the body as exhibits. Each exhibit is labelled with a letter: Exhibit "A", Exhibit "B", and so on.

Example: "Attached hereto and marked as Exhibit 'A' to this my affidavit is a true copy of the contract between the plaintiff and the defendant dated March 15, 2025."

5. The Jurat (Swearing Clause)

The final section is the jurat — the part where you sign the affidavit in front of a commissioner. It typically reads:

"SWORN (or AFFIRMED) before me at the City of Toronto, in the Province of Ontario, on April 6, 2026."

Below this are signature lines for both you (the deponent) and the commissioner.

Swearing vs. Affirming

You can either swear the affidavit (on a religious text) or affirm it (a solemn declaration without religious content). Both have exactly the same legal effect. The choice is entirely yours.

Who Can Commission an Affidavit?

An affidavit must be sworn or affirmed before a person authorized to administer oaths. In Canada, this includes:

Lawyers and paralegals (in most provinces)
Notaries public
Commissioners of oaths — many court offices have commissioners available
Certain public officials — justices of the peace, municipal clerks

Cost

Many lawyers and paralegals will commission affidavits for a nominal fee ($20 to $50)
Court offices often have a commissioner available at no charge or for a small fee
Notaries public typically charge $25 to $75
Some community legal clinics offer free commissioning services

Exhibits: How to Attach Documents

When you attach documents to an affidavit, you must follow these rules:

Label each exhibit — Exhibit "A", "B", "C", etc.
Attach a cover page to each exhibit stating: "This is Exhibit [letter] referred to in the affidavit of [your name], sworn/affirmed on [date]." The commissioner signs this cover page.
Refer to each exhibit in the body of the affidavit
Use true copies — the court expects accurate, unaltered copies of the original documents
Number pages consecutively through all exhibits

Province-Specific Format Rules

Ontario

Ontario affidavits in Superior Court must comply with Rule 4.06 of the Rules of Civil Procedure and use Form 4D. Specific requirements:

Paragraphs must be numbered consecutively
The deponent must state their full name and city of residence
If the affidavit contains information based on belief (rather than personal knowledge), you must state the source of the information and that you believe it to be true (Rule 39.01(4))
Exhibits must have a blue backsheet or cover page stamped by the commissioner

British Columbia

BC affidavits in Supreme Court follow the Supreme Court Civil Rules (Rule 22-2). Key differences:

The standard form is Form 62
Affidavits must be typed or printed on standard letter-size paper
Exhibits are marked by the commissioner with their signature and a description

Alberta

Alberta affidavits follow the Alberta Rules of Court (Part 13). Requirements include:

Form 49 for general affidavits
The affidavit must state the deponent's occupation and address
Virtual commissioning is available under certain conditions

Quebec

Quebec uses a different system. Sworn statements (déclarations sous serment) are used in some proceedings, but the Code of Civil Procedure relies more heavily on written declarations and testimony than traditional common-law affidavits.

Common Mistakes

Including hearsay without proper attribution — if you must include secondhand information, clearly state the source and that you believe it to be true
Including opinions or legal arguments — an affidavit is for facts. Save your arguments for your factum or submissions
Forgetting to attach exhibits — if you refer to Exhibit "C" but do not attach it, the court cannot consider it
Not having it properly commissioned — an unsigned or unsworn affidavit is not valid evidence
Signing before meeting the commissioner — you must sign the affidavit in front of the commissioner. Do not sign it in advance
Sloppy formatting — courts expect professional presentation. Number your paragraphs, use clear headings, and proofread carefully

How ProSe Can Help

ProSe helps self-represented litigants prepare properly formatted affidavits through a straightforward questionnaire. Answer plain-language questions about your situation, and ProSe generates a document that follows the correct format for your province and court level.

Start for free at BeProSe.ca — your first document costs nothing.

Key Resources

Ontario Rules of Civil Procedure — Form 4D — e-Laws Ontario (ontario.ca/laws)
BC Supreme Court Civil Rules — Form 62 — bclaws.gov.bc.ca
Alberta Rules of Court — Form 49 — albertacourts.ca
Steps to Justice — Affidavits — stepstojustice.ca
Community Legal Education Ontario (CLEO) — cleo.on.ca

Last reviewed: April 2026. This article is for general informational purposes only and does not constitute legal advice. Court rules vary by province. For advice specific to your situation, consult a licensed lawyer or paralegal.