New York Third-Party Complaint: 90-Day Deadline and Filing Rules

A New York third-party complaint is how a defendant pulls a new party into an existing lawsuit, on the theory that the new party owes the defendant indemnification or contribution for what the plaintiff is seeking. It is filed under CPLR 1007, and for cases commenced on or after April 18, 2026, the AVOID Act gives the defendant just 90 days after serving the answer to file without court permission. Miss that window and the court must sever or dismiss the third-party claim.

When You Can Implead Someone

CPLR 1007 lets a defendant bring in a person “who is or may be liable to that defendant for all or part of the plaintiff’s claim.”¹ The word “derivative” captures the idea: the third-party defendant’s liability has to flow from the defendant’s liability to the plaintiff. You cannot use impleader to collect on an unrelated debt from someone who happens to be a convenient target. In George Cohen Agency, Inc. v. Donald S. Perlman Agency, Inc., the Court of Appeals held that the third-party defendant’s liability must arise from the defendant’s liability to the plaintiff in the original complaint.²

Third-party claims usually fall into one of three buckets:

Contractual indemnity, where a written agreement (common in construction and commercial leases) requires the third party to cover the loss.
Common-law indemnity, where a party without direct fault is held liable through vicarious liability or a statute and seeks to shift the full loss to the actual wrongdoer.
Contribution under CPLR 1401, where two or more parties liable for the same injury split responsibility in proportion to fault.³

The 90-Day Filing Deadline

For lawsuits commenced on or after April 18, 2026, the AVOID Act (“Avoiding Vexatious Overuse of Impleading to Delay”) gives a defendant 90 days after serving the answer to file a third-party complaint without court permission.⁴ The old window was 120 days, so guidance written before 2026 will show that longer number.

After the 90 days, you need a court order to file. Once the Note of Issue has been filed and the case is trial-ready, the bar rises again: you must show good cause or that allowing the filing serves the interest of justice. Courts must sever or dismiss any third-party complaint filed in violation of these deadlines, and a severed third-party action cannot later be re-consolidated with the main case.

There is one narrow exception. A defendant may file a third-party complaint against the plaintiff’s employer outside the standard deadlines, without a court order, if the claim seeks indemnification or contribution for a “grave injury” under Workers’ Compensation Law Section 11, or if the employer’s identity was not known until after the normal deadline passed. Even then, the complaint has to be filed within 90 days of learning the employer’s identity or discovering the grave injury, whichever is later.

For cases already pending before April 18, 2026, the older CPLR 1007 rules still apply: filing and service within 120 days, with court approval required after that.

Drafting and Filing

The third-party summons and complaint has to lay out exactly how the new party is responsible for some or all of the plaintiff’s damages. A vague accusation of wrongdoing will not do. The pleading must connect the plaintiff’s claim against you to the third-party defendant’s obligation to indemnify or share fault, and courts routinely dismiss third-party complaints that read like a standalone claim unrelated to the main action.⁵

The third-party complaint does not get a new index number, but you pay a separate index number fee of $210 to the county clerk when filing in Supreme Court.⁶ The complaint must be indexed to the existing case and include copies of all prior pleadings served in the action.¹

E-Filing Through NYSCEF

Electronic filing through NYSCEF is mandatory for virtually all Supreme Court civil cases: 61 of New York’s 62 counties require it, with Allegany County the only exception.⁷ All documents upload in PDF. Attorneys and self-represented litigants need a NYSCEF account. Unrepresented parties may opt out, and attorneys who lack the technical capability may seek an exemption.

Do not send courtesy copies to the clerk or chambers unless a judge asks for them. If the court requests a working hard copy for the judge, attach the NYSCEF confirmation notice to the front.

Serving the Third-Party Defendant

After filing, the third-party summons and complaint must be served within 120 days under CPLR 306-b.⁸ This 120-day service window runs separately from the 90-day filing window: file within 90 days of serving your answer, then serve the third-party defendant within 120 days of filing.

Service methods depend on who is being served. For individuals under CPLR 308, personal delivery within New York is preferred; if that fails, you can deliver the papers to a person of suitable age at the individual’s home or workplace and mail a copy; as a last resort, you can affix the papers to the door and mail a copy, but only after showing that personal and substituted service could not be made with due diligence.⁹ For corporations under CPLR 311, deliver to an officer, director, managing agent, general agent, or cashier; for a foreign corporation authorized to do business in New York, service through the Secretary of State also works.¹⁰

Missing the 120-day service window can result in dismissal. Courts have discretion to extend for good cause or in the interest of justice, weighing diligent service attempts against prejudice to the third-party defendant. File proof of service once service is complete.

You also have to give copies of the third-party summons and complaint to the plaintiff and any co-defendants already in the case. That step triggers the plaintiff’s right under CPLR 1009 to amend the complaint and assert direct claims against the third-party defendant within 20 days after the third-party defendant’s answer is served on the plaintiff’s attorney.¹¹ If the plaintiff takes that step, the third-party defendant becomes a direct defendant in the case.

How the Third-Party Defendant Responds

A third-party defendant who has been served must answer. The deadline is 20 days after personal service within New York, or 30 days if served by another method such as substituted service, service through the Secretary of State, or service outside the state.¹²

Every allegation has to be addressed. Under CPLR 3018(a), statements the third-party defendant knows or believes to be untrue must be denied; statements the party lacks information to evaluate should be identified as such, which has the effect of a denial. Anything not specifically denied is deemed admitted.¹³ Affirmative defenses (statute of limitations, lack of jurisdiction, release, and the rest) must be pleaded or they may be waived.

CPLR 1008 gives the third-party defendant broad rights beyond simply answering. The third-party defendant can raise against the plaintiff any defenses the original defendant has to the plaintiff’s claims, except objections about improper service or lack of jurisdiction over the original defendant.¹⁴ The third-party defendant can also file counterclaims against the third-party plaintiff, cross-claims against co-defendants, and can implead yet another party under CPLR 1007 if someone else bears responsibility.

If the third-party defendant never answers, the third-party plaintiff has one year under CPLR 3215 to take steps toward entry of a default judgment. Wait longer and the court will dismiss the third-party complaint as abandoned unless sufficient cause for the delay is shown.¹⁵

The third-party defendant can also challenge the complaint by pre-answer motion under CPLR 3211(a) on grounds such as lack of subject matter jurisdiction, failure to state a cause of action, or the statute of limitations, and can argue that the impleader is improper because the third-party claim does not actually derive from the main action.¹⁶ After issue is joined, either side can move for summary judgment under CPLR 3212, generally no later than 120 days after the Note of Issue is filed.¹⁷ The court also has independent power under CPLR 1010 to dismiss a third-party complaint or order a separate trial if the third-party dispute will unduly delay the main action or prejudice any party.⁵

Statute of Limitations and Relation Back

Bringing in a new party can raise a limitations problem, especially when the underlying claim’s limitations period has already expired. Under CPLR 203(f), an amended pleading relates back to the original filing date, but only if the original pleading gave notice of the same transactions or occurrences.¹⁸

New York courts use a three-part test to decide whether a claim against a newly added party relates back. The new party must arise out of the same conduct or occurrence as the original claim, must be united in interest with an existing defendant so that it effectively had notice of the suit, and must have known or should have known it would have been named originally but for a mistake. The Court of Appeals has said the doctrine covers both simple oversights and mistakes of law, such as failing to recognize someone as a necessary party. It does not save a plaintiff who deliberately chose not to sue someone known to be potentially liable.

The point matters most when a plaintiff later wants to assert direct claims against the third-party defendant under CPLR 1009.¹¹ If limitations have run on that claim, the plaintiff needs relation back to keep it alive, even where the third-party complaint itself was timely.

Construction Cases: The Common Setting

Third-party practice shows up constantly in New York construction litigation. Under Labor Law Section 240, property owners and general contractors bear near-absolute liability for gravity-related injuries on construction sites, such as falls from scaffolds and ladders, regardless of the worker’s own negligence.¹⁹ An owner or general contractor hit with a Labor Law 240 claim will almost always implead the subcontractor whose worker was injured, seeking contractual indemnification and contribution.

These cases show why the 90-day filing deadline bites so hard. Construction disputes routinely involve multiple subcontractors, and sorting out who to implead takes time. The court must now sever or dismiss an untimely third-party complaint, and a defendant that lets the window close loses its most efficient vehicle for spreading the loss. Owners, contractors, and subcontractors in an injury case should be talking to counsel well before the 90 days runs out.

1
New York State Senate. New York CVP 1007 – When Third-Party Practice Allowed
2
CaseMine. George Cohen Agency, Inc. v. Donald S. Perlman Agency, Inc.
3
New York State Senate. New York CVP 1401 – Claim for Contribution
4
New York State Senate. New York Civil Practice Law and Rules 1007 – When Third-Party Practice Allowed
5
New York State Senate. New York Code CPLR 1010 – Dismissal or Separate Trial of Third-Party Complaint
6
New York State Unified Court System. Filing Fees – N.Y. State Courts
7
New York State Unified Court System. Annual Report on Electronic Filing – Request for Comments on E-Filing
8
New York State Senate. New York Code CVP 306-b – Service of the Summons and Complaint, Summons With Notice, Third-Party Summons and Complaint, or Petition With a Notice of Petition or Order to Show Cause
9
New York State Senate. New York Civil Practice Law and Rules 308 – Personal Service Upon a Natural Person
10
New York State Senate. New York Code CVP 311 – Personal Service Upon a Corporation or Governmental Subdivision
11
New York State Senate. New York Code CVP – R1009 – Claim by Plaintiff Against Third-Party Defendant
12
New York State Senate. New York Civil Practice Law and Rules 3012 – Service and Filing of Pleadings and Other Papers
13
New York State Senate. New York Code CVP 3018 – Responsive Pleadings
14
New York State Senate. New York Civil Practice Law and Rules 1008 – Answer
15
New York State Senate. New York Civil Practice Law and Rules 3215 – Default Judgment
16
FindLaw. New York Code CVP 3211 – Motion to Dismiss
17
New York State Senate. New York Code CVP 3212 – Motion for Summary Judgment
18
New York State Senate. New York Civil Practice Law and Rules 203 – Method of Computing Periods of Limitation
19
New York State Senate. New York Labor Law 240 – Scaffolding and Other Devices for Use of Employees