How to
Serve a Small Claims Claim
in Ontario

The Short Answer

After you file a Plaintiff's Claim, you must serve the defendant — generally within six months. An individual is usually served by personal service (someone hands them the claim) or by mail with a signed acknowledgment of receipt; a corporation is served by leaving the claim with an officer or director, or at its registered office. You then file an affidavit of service as proof. If you genuinely cannot find the defendant, you can ask the court for permission to serve a different way.

Why Proper Service Matters

Service is not a formality — it is what gives the court the authority to proceed against the defendant, and it protects the defendant's right to know they are being sued. If service is done improperly, everything built on it can collapse: a default judgment obtained on defective service can be set aside, forcing you to re-serve and redo steps. Getting service right the first time is one of the most important — and most overlooked — parts of a Small Claims Court case.

The Six-Month Deadline

Once your claim is issued, you generally have six months to serve it on the defendant. If that window passes without service, you may need to ask the court to extend the time, and an unserved claim can eventually be at risk of being dismissed for delay. Do not treat filing as the finish line — plan service promptly so you stay comfortably within the deadline.

Serving an Individual

For an individual defendant, the two most common methods are:

With mail service, delivery alone is not enough — service is generally effective when the signed acknowledgment comes back. If the card is not returned, that method has not worked and you will need another approach.

Serving a Corporation

A corporation is served differently from a person. Common methods include leaving the claim with an officer, director, or agent of the corporation, or serving it at the corporation's registered office. Different business structures have their own rules. Before serving, confirm the exact legal name and registered address of the business — this matters both for valid service and, later, for enforcing any judgment against the right entity.

Who Can Serve the Claim

A key point that trips people up: you generally cannot personally hand the claim to the defendant yourself as personal service. Personal service is carried out by someone else — often a professional process server. Some methods, like arranging mail service, can be organized by you, but the rules specify who may effect each type of service. Using a process server for personal service is common and helps ensure it is done correctly and provable.

The Affidavit of Service

Whatever method you use, you must prove it with an affidavit of service — a sworn document setting out how, when, and where the defendant was served. This is filed with the court and is essential: without valid proof of service, the court generally cannot advance the case or grant a default judgment if the defendant does not respond. Keep the affidavit and all service records organized.

When Service Is Legally Effective

A subtle but important question is when service actually counts as done, because that date starts the defendant's clock to respond. The timing depends on the method:

• Personal service is generally effective on the day the claim is handed to the defendant.
• Mail with acknowledgment of receipt is generally effective when the signed acknowledgment card is received — not when the letter is mailed.
• Service on a corporation is effective when the claim reaches the proper person or the registered office as the rules require.

This matters because the defendant's time to file a Defence (generally 20 days) runs from the effective date of service, not from when you filed the claim. Miscalculating that date can lead to a premature attempt to note the defendant in default, which the court will not accept. Recording the exact date and method of service — and capturing it accurately in your affidavit — keeps the rest of the timeline on solid footing.

If You Can’t Find the Defendant

Sometimes a defendant cannot be located, or actively avoids service. In that situation, you can ask the court for an order permitting substituted service — an alternative method (such as service by a different means reasonably likely to reach them) approved by the court. You generally need to show the steps you already took to find and serve them. Our dedicated guide on serving a defendant you can't find covers this in detail.

Common Service Mistakes

• Trying to serve the defendant yourself by hand (personal service is done by someone else)
• Assuming mailing the claim is enough, without a returned acknowledgment
• Serving the wrong entity — a business name instead of the correct corporation
• Missing the six-month service window
• Failing to complete and file a proper affidavit of service

What Happens After Service

Once the defendant is properly served, the clock starts on their time to file a Defence — generally 20 days. If they defend, the case proceeds to a settlement conference and, if needed, trial. If they do not respond within the deadline, you may be able to note them in default and seek a default judgment. Either way, valid service is the gateway to every step that follows, which is set out in our guide on how to sue in Small Claims Court.

Practical Tips for Smooth Service

• Confirm the defendant's details early — current address and, for a business, the exact legal name and registered office.
• Use a process server for personal service; they know the rules and can document the service reliably.
• Do not wait — start service soon after filing so you stay well within the six-month window.
• Keep everything — the acknowledgment card, the process server's notes, and your affidavit of service.
• Have a backup plan — if mail service fails or the defendant is evasive, know that personal service or substituted service is available.

None of this is complicated once you understand the framework, but each step has to be done correctly, because service is the foundation everything else rests on. Where the defendant is a corporation, is hard to locate, or is deliberately avoiding you, that is exactly the situation where a paralegal or process server earns their fee — a small investment compared with the cost of a judgment later set aside for defective service.

Common Myths

Myth: “I can just hand the papers to them myself.”

False. You generally cannot personally serve the defendant yourself — personal service is done by someone else, often a process server.

Myth: “Mailing the claim counts as service.”

Not by itself. Service by mail generally requires a signed acknowledgment of receipt to come back; delivery alone is not enough.

Myth: “If I can't find them, I can't sue them.”

False. If a defendant cannot be located or is evading service, you can ask the court for permission to serve a different way.

Frequently Asked Questions