What the court expects
An affidavit filed in an Ontario proceeding must be sworn or affirmed before a person authorized to take affidavits, with a completed jurat showing where and when it was sworn and who took it. Court staff and opposing counsel do check — a missing jurat entry, an unsigned exhibit stamp or a signature made before the appointment can get the document rejected or challenged.
Sign in front of the commissioner, not before
The single most common mistake is signing at home. The oath and the signature belong together: the commissioner must administer the oath or affirmation and watch you sign. If you've already signed, expect to re-sign a fresh copy in the commissioner's presence.
Exhibits need their own treatment
Each document attached to an affidavit is an exhibit, and each exhibit needs an exhibit stamp or certificate — 'This is Exhibit A referred to in the affidavit of…' — signed by the commissioner. Bring every exhibit, in order, unstapled from the affidavit, and make sure the affidavit's references (Exhibit A, B, C) match what you attach.
Remote commissioning for court documents
Ontario permits affidavits to be commissioned by video where the requirements for remote commissioning are met, and courts routinely accept them. The jurat will reflect that the affidavit was commissioned remotely. If your matter involves an unusual court or tribunal, confirm its practice before relying on video.
What commissioning is not
The commissioner confirms your oath — they do not review your evidence, fix your draft or advise whether the affidavit helps your case. If you need the content checked, that is legal advice: speak to a lawyer before the commissioning appointment, not during it.