Upon timely motion, any person may be permitted to intervene in any action when a statute of the state confers a right to intervene in the discretion of the court, or when the person’s claim or defense and the main action have a common question of law or fact. In exercising its discretion, the court shall consider whether the intervention will unduly delay the determination of the action or prejudice the substantial rights of any party.
§ 1013.Intervention by permission
Article 10. Parties Generally · Last amended 1963 · Last verified July 21, 2026
In one sentenceCPLR 1013 lets a court permit intervention, at its discretion, when a statute allows discretionary intervention or when the intervenor's claim or defense shares a common question of law or fact with the pending action, weighing undue delay and prejudice to existing parties.
Full Text of CPLR 1013
Plain-English Summary
Not every intervenor has an absolute right to join a case. CPLR 1013 covers the discretionary version: on a timely motion, a court may -- but need not -- permit someone to intervene when a statute gives the court that discretion, or when the person's claim or defense shares a common question of law or fact with the pending action.
That common-question standard is broader than the tighter categories in CPLR 1012, but the tradeoff is that permission, not right, governs the outcome. The court decides whether letting the new party in serves the case, rather than being required to let them in.
To make that call, the rule directs the court to weigh whether granting intervention will unduly delay the case or prejudice the substantial rights of the parties already in it. A motion filed late in the litigation, or one that would force the parties to relitigate settled ground, is more likely to run into that limit than one filed early, before the case has taken shape.
Frequently Asked Questions
What is permissive intervention in New York?
Permissive intervention under CPLR 1013 lets a court, in its discretion, allow someone to join a pending case when their claim or defense shares a common question of law or fact with the action, or when a statute gives the court discretion to allow it.
What is the difference between CPLR 1012 and CPLR 1013?
CPLR 1012 covers intervention as of right, which the court must grant when the statute's conditions are met; CPLR 1013 covers permissive intervention, which the court may grant or deny based on its own judgment.
What factors does a court weigh under CPLR 1013?
The court considers whether allowing intervention will unduly delay the determination of the action or prejudice the substantial rights of any party already involved.
Can I intervene in a New York case if my claim just shares some facts with it?
Yes, potentially. CPLR 1013 allows permissive intervention when your claim or defense and the main action share a common question of law or fact, though the court retains discretion to deny the motion.
Do I need to file anything besides a motion to intervene under CPLR 1013?
Advisory Committee Notes
This section is derived from CPA § 193-b(2), substantially unchanged; Cf. CPA § 988 (part of first sentence).
Amendment History
Add, L 1962, ch 308, eff Sept 1, 1963.
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
Also known as: CPLR 1013 New Yorkpermissive intervention New Yorkdiscretionary intervention CPLRcommon question of law or fact interventionmotion to intervene New York lawsuitjoining a lawsuit as intervenor New Yorkintervene by permission New York court