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Ohio's affidavit of merit: one per defendant, filed with the complaint

Ohio procedure · Last verified August 17, 2026

Ohio puts the expert gate in the pleading rule. A complaint containing a medical, dental, optometric or chiropractic claim must arrive with an affidavit of merit — one for each defendant against whom expert testimony is needed — and the affidavit has three required statements. The extension exists, but it must be requested at the same moment, in a motion filed with the complaint.

The consolation is that dismissal for non-compliance is not a merits dismissal.

The requirement

Civ.R. 10(D)(2)(a):

Except as provided in division (D)(2)(b) of this rule, a complaint that contains a medical claim, dental claim, optometric claim, or chiropractic claim, as defined in R.C. 2305.113, shall be accompanied by one or more affidavits of merit relative to each defendant named in the complaint for whom expert testimony is necessary to establish liability. Affidavits of merit shall be provided by an expert witness meeting the requirements of Evid.R. 702 and, if applicable, also meeting the requirements of Evid.R. 601(B)(5).

Three qualifications in that sentence.

"Accompanied by" — the affidavit travels with the complaint, not afterwards.

"Relative to each defendant ... for whom expert testimony is necessary" — the count is per defendant, and it is driven by whether expert proof is needed against that defendant, not by how many defendants there are.

The affiant must qualify under Evid.R. 702, and where applicable under Evid.R. 601(B)(5), the competency rule for expert testimony on liability in medical claims.

The three statements

The same subdivision prescribes the contents exactly:

Affidavits of merit shall include all of the following: (i) A statement that the affiant has reviewed all medical records reasonably available to the plaintiff concerning the allegations contained in the complaint; (ii) A statement that the affiant is familiar with the applicable standard of care; (iii) The opinion of the affiant that the standard of care was breached by one or more of the defendants to the action and that the breach caused injury to the plaintiff.

All three, in every affidavit. Note the first: it is a statement about records reasonably available to the plaintiff, not about the complete record — which is what makes the affidavit possible before discovery.

Note also the third: the opinion must cover breach and causation. An affidavit that establishes a standard of care and stops short is incomplete on the face of the rule.

Buying time: the motion filed with the complaint

Civ.R. 10(D)(2)(b) is the safety valve, and its second sentence is the trap:

The plaintiff may file a motion to extend the period of time to file an affidavit of merit. The motion shall be filed by the plaintiff with the complaint. For good cause shown and in accordance with division (c) of this rule, the court shall grant the plaintiff a reasonable period of time to file an affidavit of merit, not to exceed ninety days, except the time may be extended beyond ninety days if the court determines that a defendant or non-party has failed to cooperate with discovery or that other circumstances warrant extension.

The motion is filed with the complaint. Not later, not when the ninety days is needed — at filing. A plaintiff who files without an affidavit and without the motion has no route to the extension in the rule.

Two other features. On good cause the court "shall grant" a reasonable period — the grant is mandatory once good cause is shown, though the length is the court's. And the ninety days is not an absolute ceiling: it may be exceeded where a defendant or non-party has failed to cooperate with discovery, or where other circumstances warrant.

What "good cause" means

Civ.R. 10(D)(2)(c) lists what the court weighs, which doubles as a drafting checklist for the motion:

In determining whether good cause exists to extend the period of time to file an affidavit of merit, the court shall consider the following: (i) A description of any information necessary in order to obtain an affidavit of merit; (ii) Whether the information is in the possession or control of a defendant or third party; (iii) The scope and type of discovery necessary to obtain the information; (iv) What efforts, if any, were taken to obtain the information; (v) Any other facts or circumstances relevant to the ability of the plaintiff to obtain an affidavit of merit.

Five factors, and four of them are about specific information you cannot get. A motion that says the expert needs more time, without identifying what information is missing, who holds it, and what was done to get it, is not addressing the rule's own list.

What the affidavit is, and is not

Civ.R. 10(D)(2)(d) does two separate things:

An affidavit of merit is required to establish the adequacy of the complaint and shall not otherwise be admissible as evidence or used for purposes of impeachment. Any dismissal for the failure to comply with this rule shall operate as a failure otherwise than on the merits.

The affidavit is a pleading requirement — it tests the adequacy of the complaint, not the merits of the claim. It is inadmissible as evidence and cannot be used to impeach the expert later.

And the consequence of non-compliance is a dismissal otherwise than on the merits. That phrase is the Ohio Civil Rules' term of art for a dismissal that is not an adjudication on the merits, which matters a great deal to whether the claim can be brought again.

That is a materially softer regime than Texas, where a missed expert-report deadline produces dismissal with prejudice plus mandatory fees — compare the Texas expert report deadline.

Where this sits in Ohio pleading practice

Civ.R. 10(D)(2) is a subdivision of the general rule on the form of pleadings — the same rule that governs captions, numbered paragraphs, adoption by reference, and the requirement in Civ.R. 10(D)(1) that a claim founded on an account or written instrument attach a copy or explain its absence. Reading (D)(1) and (D)(2) together makes the design obvious: both are about what must be attached to a pleading for it to be adequate.

A challenge to the affidavit is therefore an attack on the sufficiency of the complaint, and belongs alongside the Civ.R. 12 practice described in the Ohio motion to dismiss — but it is a distinct requirement with its own rule, its own contents and its own extension mechanism.

How Ohio compares to the federal rules

OhioFederal
Expert affidavit with the complaintrequired in medical, dental, optometric and chiropractic claimsno counterpart
Where the requirement sitsthe form-of-pleadings rulenot applicable
Number requiredone or more per defendant needing expert proofnot applicable
Affiant's qualificationsEvid.R. 702, and Evid.R. 601(B)(5) where applicableRule 702 at trial or summary judgment
Required contentsrecords reviewed, familiarity with the standard, breach and causationnot applicable
Extensionmotion filed with the complaint; up to 90 days, extendablenot applicable
Standard for extensiongood cause, on five listed factorsnot applicable
Affidavit admissible at trialno, and not usable for impeachmentexpert reports generally inadmissible
Effect of non-compliancedismissal otherwise than on the meritsnot applicable

The federal rules test the expert late, under Rule 702. Ohio tests the paperwork at the door — but, unlike some states, leaves the door open afterwards.

A short checklist

  • Count your defendants, not your claims. One or more affidavits for each defendant needing expert proof.
  • Check the affiant against Evid.R. 702 and, where it applies, Evid.R. 601(B)(5).
  • Include all three statements. Records reviewed, familiarity with the standard, and an opinion covering breach and causation.
  • If you need time, move with the complaint. The motion has the same filing moment as the pleading.
  • Write the motion to the five factors — what information is missing, who has it, what discovery is needed, what you have already tried.
  • Ask for more than 90 days only on the stated grounds — non-cooperation with discovery, or other warranting circumstances.
  • Do not plan to use the affidavit as evidence. It is inadmissible and cannot impeach.
  • If the case is dismissed for non-compliance, note that it is otherwise than on the merits.

Where these rules live

This page explains what the rule says; it is not legal advice. Whether a claim is a "medical claim" as defined in R.C. 2305.113 — and therefore whether the rule applies at all — is a statutory question this page does not answer.

How this guide is sourced. Every procedural statement here is drawn from the text of the rules named above, each of which is reproduced verbatim on its own page on this site. Quoted rule language appears in quotation marks or block quotes; everything else is original writing. Last verified August 17, 2026.
This page explains what the rules say. It is legal information, not legal advice, and it cannot tell you how a rule applies to your situation. Deadlines are often short and some are not extendable — if the outcome matters, talk to a lawyer or your court’s self-help center.