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Late Expert Reports

Late Expert Reports

Warren WhiteKnight

Written by Warren WhiteKnight

Published: August 25, 2026

Whether it’s a car accident, slip and fall, or a medical malpractice case, late expert reports have always been a plague on our civil justice system, particularly in the practice of personal injury law. The Rules with respect to the timing of expert reports has always been such that reports were required to be served 90 or 60 days in advance of pre-trial. However, the Rule as formerly worded was so permissive that counsel frequently broke this Rule, and the Court frequently let these reports in.

This has since changed following amendments to Rule 53.08 in 2022. Since those amendments our firm has been fortunate to win two of the now leading cases on exclusion of late expert reports:

  • Nykilchuk v. 2244301 Ontario Inc. et al, ONSC 5025
  • Tyner v. Phillips, 2023 ONSC 5207 (CanLII)

Both of these decisions relied upon changes to Rule 53.08 which flipped the presumption of the admissibility of late reports on its head. When a party attempts to have late expert reports admitted, the new Rule requires that:

  1. There is a reasonable explanation for the failure; and
  2. Granting leave would not,
    1. Cause prejudice to the opposing party that could not be compensated for by costs or an adjournment, or
  3. Cause undue delay in the conduct of the trial.

Our firm won both of these motions on the basis that the Defendant could not pass the test of “a reasonable explanation for the failure”. Accordingly, both Defendants were denied the ability to obtain expert reports, and thus were faced with going to trial against the Plaintiff who had numerous reports. In the Tyner case, Justice Muszynski said: “I find that there is no explanation for the delay in bringing this motion to compel the plaintiff to attend a defence medical examination.”

At both motions the Defendants argued that they would be “prejudiced” if they were not able to obtain expert reports. In the Nykilchuk case Justice Fortier said: “…if the defendants are now disadvantaged in any way, it was self-inflicted.”.

R.S.J Edwards has made clear in his decision in Agha v. Munroe, 2022 ONSC 2508 and more recently in Longo v. Westin Hotel Management, L.P., 2024 ONSC 3676 that “[l]awyers and litigants need to adapt to the new rule immediately. The late deliver of expert reports simply will not be rubber-stamped by the court.”

The decisions cited in this article have come from the Courts in Kingston, Oshawa and Ottawa, and it’s clear that each courthouse in Ontario is starting to take these issues very seriously, and hold litigants to the Rules.

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