Ontario Civil Procedure Rules Amendments Now in Force

Ontario's Rules of Civil Procedure amendments, specifically Ontario Regulation 275/26 under the Courts of Justice Act, came into force on September 1, 2026, introducing new quotation accuracy obligations for lawyers and expert witnesses.

This significant regulatory update directly impacts litigation practice across Ontario by imposing a heightened standard for the verification of cited authorities. The amendments, particularly subrule 4.06.1(2.1) for lawyers and subrule 53.03(2.1), paragraph 6.3 for expert witnesses, now require certification that every quotation from any authority, document, or record in factums and expert reports is an accurate reproduction. This move is a direct response to reported incidents of AI-generated content leading to fabricated or inaccurately quoted legal authorities, underscoring a critical need for enhanced due diligence in legal submissions. The change aims to bolster the integrity of legal proceedings and ensure the reliability of information presented to the courts.

The legal context for these amendments is rooted in Regulation 194 of the Revised Regulations of Ontario, 1990, which governs civil procedure province-wide. The Civil Rules Committee filed Ontario Regulation 275/26, which was subsequently approved by Attorney General Doug Downey. Beyond the new quotation accuracy rules, the amendments also encompass changes to factums, expert reports, and a revised Form 53 (Acknowledgment of Expert’s Duty), dated June 1, 2026, which replaces the previous version. This updated form must be used for any expert report served after September 1, 2026. While the Ontario government anticipates no regulatory impact on businesses, the operational impact on legal professionals is substantial.

Key parties involved in this regulatory shift include the Ontario government, the Civil Rules Committee, Attorney General Doug Downey, and, most directly, all lawyers and expert witnesses practicing within Ontario's civil justice system. The courts will also play a role in enforcing these new standards. For practitioners, the immediate takeaway is the imperative to review and adapt internal practices to ensure strict compliance with these new requirements. This includes implementing robust verification protocols for all cited authorities, especially in an era where AI tools are increasingly used in legal research and drafting. Law firms should update their internal guidelines, provide training to staff on the revised rules, and ensure that the correct, updated Form 53 is consistently used for all expert reports to avoid procedural non-compliance and potential professional repercussions.