Rule 15.Amended and Supplemental Pleadings

Last amended July 1, 2013 · Last verified July 1, 2026

In one sentenceRule 15 tells a party how and when a pleading may be amended — once without permission early in the case, otherwise with the court’s leave freely given, with an amendment relating back to the original filing date when it grows out of the same conduct already at issue, plus a path for supplementing a pleading with events that happened after the case began.

Full Text of Rule 15

Text sizeJump to: (A) (B) (C) (D) (E)

(A) Amendments

A party may amend its pleading once as a matter of course within twenty-eight days after serving it or, if the pleading is one to which a responsive pleading is required within twenty-eight days after service of a responsive pleading or twenty-eight days after service of a motion under Civ.R. 12(B), (E), or (F), whichever is earlier. In all other cases, a party may amend its pleading only with the opposing party’s written consent or the court’s leave. The court shall freely give leave when justice so requires. Unless the court orders otherwise, any required response to an amended pleading must be made within the time remaining to respond to the original pleading or within fourteen days after service of the amended pleading, whichever is later.

(B) Amendments to conform to the evidence

When issues not raised by the pleadings are tried by express or implied consent of the parties, they shall be treated in all respects as if they had been raised in the pleadings. Such amendment of the pleadings as may be necessary to cause them to conform to the evidence and to raise these issues may be made upon motion of any party at any time, even after judgment. Failure to amend as provided herein does not affect the result of the trial of these issues. If evidence is objected to at the trial on the ground that it is not within the issues made by the pleadings, the court may allow the pleadings to be amended and shall do so freely when the presentation of the merits of the action will be subserved thereby and the objecting party fails to satisfy the court that the admission of such evidence would prejudice him in maintaining his action or defense upon the merits. The court may grant a continuance to enable the objecting party to meet such evidence.

Whenever the claim or defense asserted in the amended pleading arose out of the conduct, transaction, or occurrence set forth or attempted to be set forth in the original pleading, the amendment relates back to the date of the original pleading. An amendment changing the party against whom a claim is asserted relates back if the foregoing provision is satisfied and, within the period provided by law for commencing the action against him, the party to be brought in by amendment (1) has received such notice of the institution of the action that he will not be prejudiced in maintaining his defense on the merits, and (2) knew or should have known that, but for a mistake concerning the identity of the proper party, the action would have been brought against him.

The delivery or mailing of process to this state, a municipal corporation or other governmental agency, or the responsible officer of any of the foregoing, subject to service of process under Rule 4 through Rule 4.6, satisfies the requirements of clauses (1) and (2) of the preceding paragraph if the above entities or officers thereof would have been proper defendants upon the original pleading. Such entities or officers thereof or both may be brought into the action as defendants.

(D) Amendments where name of party unknown

When the plaintiff does not know the name of a defendant, that defendant may be designated in a pleading or proceeding by any name and description. When the name is discovered, the pleading or proceeding must be amended accordingly. The plaintiff, in such case, must aver in the complaint the fact that he could not discover the name. The summons must contain the words "name unknown," and a copy thereof must be served personally upon the defendant.

(E) Supplemental pleadings

Upon motion of a party the court may, upon reasonable notice and upon such terms as are just, permit him to serve a supplemental pleading setting forth transactions or occurrences or events which have happened since the date of the pleading sought to be supplemented. Permission may be granted even though the original pleading is defective in its statement of a claim for relief or defense. If the court deems it advisable that the adverse party plead to the supplemental pleading, it shall so order, specifying the time therefor.

End

Amendment History

Effective Date: July 1, 1970

Amended: July 1, 2013

Staff Note (July 1, 2013 Amendment)

Rule 15(A) is amended to allow amendment without leave of court of a complaint, or other pleading requiring a responsive pleading, for a period of 28 days after the service of a responsive pleading or motion. Under the prior rule, amendment without leave of court was limited to pleadings not requiring a response or to which a required response had not been served.

Rule 15(A) is also amended to limit amendment without leave of court of a complaint or other pleading requiring a responsive pleading, to a period of 28 days after service of the pleading when a response has not been served. Under the prior rule, the time for amendment without leave of court under those circumstances was not limited, and could be made at any time prior to service of a response.

The 2013 changes to Civ.R. 15(A) are modeled on the 2009 amendments to Fed.R.Civ.P. 15(a) and made for the same reasons that prompted those amendments.

Plain-English Summary

Division (A) lets a party amend a pleading once as a matter of course within twenty-eight days after serving it, or, if a responsive pleading is required, within twenty-eight days after service of that response or of a motion under Civ.R. 12(B), (E), or (F), whichever comes first. Beyond that window, amendment requires either the opposing party's written consent or leave of court, which the rule directs courts to give freely when justice requires. Division (B) treats an issue tried by the express or implied consent of the parties as though it had been raised in the pleadings all along, even allowing amendment during or after trial to conform the pleadings to the evidence presented at trial.

Division (C) lets an amendment relate back to the date of the original pleading whenever the claim or defense grew out of the same conduct, transaction, or occurrence already set out or attempted to be set out there — including an amendment that changes the party sued, so long as that party received timely notice of the action and knew or should have known that, but for a mistake about identity, the action would have named it from the start. Division (D) lets a defendant whose name is unknown be sued under any name and description, with the pleading amended once the true name is discovered and the summons served personally.

Division (E) permits a party, with the court's permission and on just terms, to file a supplemental pleading setting out events that happened after the original pleading was filed, whether or not the original pleading was itself defective, without requiring a response unless the court orders one.

Frequently Asked Questions

How long does a party have to amend a pleading without asking the court?

Twenty-eight days after serving the original pleading, or, for a pleading that requires a response, twenty-eight days after service of that response or of a motion under Civ.R. 12(B), (E), or (F) — whichever comes first. After that, amendment requires the other side’s written consent or the court’s leave.

What does it mean for an amendment to “relate back” to the original complaint?

Under Rule 15(C), an amendment that arises from the same conduct, transaction, or occurrence as the original pleading is treated as filed on the original filing date — which can save a claim that would otherwise be barred by the statute of limitations once the amendment is allowed.

What is a supplemental pleading, and how is it different from an amended pleading?

A supplemental pleading adds transactions or events that happened after the original pleading was filed, while an amended pleading corrects or adds to matters that existed but were overlooked or unknown at the time. Rule 15(E) requires the court’s permission for a supplemental pleading.

Source & verification. The rule text, Effective Date, Amended dates, and Staff Notes are reproduced verbatim from the official Ohio Rules of Civil Procedure (Ohio R. Civ. P. 15). Prescribed by the Supreme Court of Ohio (Ohio Constitution, Art. IV, § 5(B)). The plain-English summary is original and written by us. Last verified July 1, 2026. · Official source

Also known as: amended pleadingssupplemental pleadingsrelation backleave to amend