(a) Intervention as of right. Upon timely motion, any person shall be permitted to intervene in any action: 1. when a statute of the state confers an absolute right to intervene; or 2. when the representation of the person’s interest by the parties is or may be inadequate and the person is or may be bound by the judgment; or 3. when the action involves the disposition or distribution of, or the title or a claim for damages for injury to, property and the person may be affected adversely by the judgment.
§ 1012.Intervention as of right; notice to attorney-general, city, county, town or village where constitutionality in issue.
Article 10. Parties Generally · Last amended 2005 · Last verified July 21, 2026
In one sentenceCPLR 1012 gives a person an absolute right to intervene when a statute confers that right, when existing parties may not adequately protect the person's interest and a judgment could bind them, or when property they have a stake in is at issue.
Full Text of CPLR 1012
(b) Notice to attorney-general, city, county, town or village where constitutionality in issue. 1. When the constitutionality of a statute of the state, or a rule and regulation adopted pursuant thereto is involved in an action to which the state is not a party, the attorney-general, shall be notified and permitted to intervene in support of its constitutionality. 2. When the constitutionality of a local law, ordinance, rule or regulation of a city, county, town or village is involved in an action to which the city, county, town or village that enacted the provision is not a party, such city, county, town or village shall be notified and permitted to intervene in support of its constitutionality. 3. The court having jurisdiction in an action or proceeding in which the constitutionality of a state statute, local law, ordinance, rule or regulation is challenged shall not consider any challenge to the constitutionality of such state statute, local law, ordinance, rule or regulation unless proof of service of the notice required by this subdivision is filed with such court.
(c) Notice to comptroller of the state of New York where public retirement benefits are in issue. Where public retirement benefits, paid, payable, claimed, or sought to be paid by a state retirement system or any other retirement system established for public employees within this state or any subdivision thereof, or the interpretation of any provisions of law or rules governing any such retirement system or the operation thereof, are involved in an action to which the comptroller of the state of New York is not a party, the court shall notify said comptroller, who shall be permitted, in his discretion, to intervene in such action or to file a brief amicus curiae.
Plain-English Summary
Intervention lets an outsider join a lawsuit already underway, and CPLR 1012(a) defines the three situations where that right is absolute rather than left to the court's discretion. A statute might grant the right directly. The existing parties might not adequately protect the would-be intervenor's interest, while a judgment could still bind that person. Or the case might involve property, or a claim for damages to it, in which the person has a stake that a judgment could affect. In any of these three situations, a timely motion to intervene must be granted.
Subdivision (b) adds a separate notice requirement aimed at a different concern: making sure the government gets a chance to defend its own laws. When a lawsuit challenges the constitutionality of a state statute or a related rule or regulation, and the state itself isn't already a party, the attorney general has to be notified and given the chance to intervene in defense of it. The same goes for a city, county, town, or village whose local law, ordinance, rule, or regulation is under constitutional attack -- if that government isn't already a party, it must be notified and permitted to intervene. Courts can't even reach the constitutional question without proof that this notice was given.
Subdivision (c) extends a similar, though softer, notice duty to the state comptroller. When a case touches public retirement benefits, or the interpretation of the laws or rules governing a public retirement system, and the comptroller isn't already a party, the court must notify that office. Unlike the attorney general or local government notice, the comptroller isn't guaranteed intervention -- the office can choose to intervene, or instead file an amicus brief, at its own discretion.
Frequently Asked Questions
How do I intervene in a New York lawsuit?
You file a timely motion to intervene, accompanied by a proposed pleading under CPLR 1014; CPLR 1012 grants intervention as of right in three situations -- a statute confers the right, the existing parties may not adequately protect your interest and you may be bound by the judgment, or the case involves property or damages to property you have a stake in.
What is intervention as of right in New York?
It's a category of intervention under CPLR 1012(a) that a court must grant on a timely motion, as opposed to permissive intervention under CPLR 1013, which the court may grant or deny in its discretion.
When must the New York attorney general be notified of a lawsuit?
CPLR 1012(b) requires notice to the attorney general, with an opportunity to intervene, whenever a lawsuit challenges the constitutionality of a state statute or a related rule or regulation and the state isn't already a party.
What happens if I challenge a law's constitutionality without notifying the attorney general?
Under CPLR 1012(b), the court cannot consider the constitutional challenge unless proof that the required notice was served has been filed with the court.
Does a city have a right to intervene when its local law is challenged?
Yes. CPLR 1012(b) requires that a city, county, town, or village be notified and permitted to intervene when the constitutionality of its own local law, ordinance, rule, or regulation is at issue in a case where it isn't already a party.
Does the state comptroller have to intervene in public retirement benefit cases?
No. CPLR 1012(c) requires the court to notify the comptroller when public retirement benefits or retirement system rules are at issue, but leaves it to the comptroller's discretion whether to intervene or instead file an amicus brief.
Advisory Committee Notes
Subd (a) is derived from CPA § 193-b(1), substantially unchanged. Subd (b) is new. As to the provision for notification to the attorney general in this section, see § 71 of the Executive Law, which corresponds, in a general way, to the Federal statute referred to in Federal rule 24(c). However, there are differences between the state and the Federal statutes which prevent using the pertinent language of rule 24(c). The state statute is somewhat complicated and the simple provision incorporated in this section is believed to suffice; there is no actual inconsistency between § 71 of the Executive Law and this section.
Amendment History
Add, L 1962, ch 308, eff Sept 1, 1963; amd, L 1972, ch 360, § 1, eff Sept 1, 1972; L 2003, ch 296, § 7, eff Jan 1, 2005.
Source & verification. Provision text, History, and Advisory
Committee Notes are reproduced verbatim from the Consolidated Laws of New York.
Last verified July 21, 2026.
· Official source
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