In an action against a person whose name is unknown to the plaintiff: (a) He shall be described in the complaint and process as unknown defendant, (b) if his name and place of residence, or either, be discovered by the plaintiff pending the action, the complaint shall be amended accordingly.
Rule 4.15.Unknown defendant.
Current through June 18, 2026 · Last verified July 9, 2026
In one sentenceWhen a plaintiff does not know a defendant's name, the complaint and process may describe that person as an unknown defendant, and the plaintiff must amend the complaint once the name or address comes to light during the case.
Full Text of Rule 4.15
Amendment History
(Amended October 18, 1977, effective January 1, 1978.)
Plain-English Summary
Sometimes a plaintiff knows a wrong was done but not who did it — a hit-and-run driver, an unidentified employee, a John Doe defendant in a property dispute. Rule 4.15 lets the plaintiff file suit anyway, naming that person as an unknown defendant in both the complaint and the summons. The case can move forward without waiting to track the person down first.
The rule also creates an obligation. Once the plaintiff learns the person's name, place of residence, or either one, the complaint must be amended to reflect it. The rule does not set a separate deadline of its own for that amendment, but it makes clear the plaintiff cannot keep litigating against a placeholder name after learning who the real party is.
Frequently Asked Questions
Can I sue someone in Kentucky if I don't know their name?
Yes. Rule 4.15 allows a complaint and the summons to describe the person as an unknown defendant when the plaintiff does not know their name.
What happens once I find out the defendant's real name?
The complaint must be amended to identify the defendant once the plaintiff discovers the name, place of residence, or either one, while the action is pending.
Does this rule cover a defendant whose address is unknown but whose name is known?
The rule addresses a person whose name is unknown to the plaintiff. It requires amendment once the name or residence, or either, is discovered.
Source & verification. The rule text is reproduced verbatim from the
official Kentucky Rules of Civil Procedure (Ky. R. Civ. P. 4.15). Prescribed by the Supreme Court of Kentucky (Ky. Const. § 116). The plain-English summary is original and written by us. Last verified July 9, 2026. ·
Official source
Also known as: suing a John Doe defendant in Kentuckyunknown defendant rulehow to sue someone whose name I do not knowamending a complaint after learning a defendant identityplaceholder defendant in a lawsuit