(a) Parties who should be joined. Persons who ought to be parties if complete relief is to be accorded between the persons who are parties to the action or who might be inequitably affected by a judgment in the action shall be made plaintiffs or defendants. When a person who should join as a plaintiff refuses to do so he may be made a defendant.
§ 1001.Necessary joinder of parties
Article 10. Parties Generally · Last amended 1963 · Last verified July 21, 2026
In one sentenceCPLR 1001 requires that anyone needed for complete relief, or who might be hurt by the judgment, be joined as a plaintiff or defendant, and lets the court proceed without an absent required party when joining them is not possible and fairness allows it.
Full Text of CPLR 1001
(b) When joinder excused. When a person who should be joined under subdivision (a) has not been made a party and is subject to the jurisdiction of the court, the court shall order him summoned. If jurisdiction over him can be obtained only by his consent or appearance, the court, when justice requires, may allow the action to proceed without his being made a party. In determining whether to allow the action to proceed, the court shall consider:
1. whether the plaintiff has another effective remedy in case the action is dismissed on account of the nonjoinder; 2. the prejudice which may accrue from the nonjoinder to the defendant or to the person not joined; 3. whether and by whom prejudice might have been avoided or may in the future be avoided; 4. the feasibility of a protective provision by order of the court or in the judgment; and 5. whether an effective judgment may be rendered in the absence of the person who is not joined.
Plain-English Summary
CPLR 1001 sorts out who has to be in a lawsuit before the court can resolve it. Subdivision (a) names two groups: people needed for the court to grant complete relief, and people who might suffer an unfair result from a judgment they never had a chance to contest. Both belong in the case, as plaintiffs or defendants. A person who should sue but won't step forward as plaintiff can be named a defendant instead, which lets the case move without letting that holdout block it.
Subdivision (b) covers what happens when a required party is missing. If the court can reach that person with process, the fix is easy: the court orders them summoned into the case. The harder question comes up when the only way to get jurisdiction over that person depends on their own consent or voluntary appearance, something a court can't compel. There, the court weighs five factors: whether the plaintiff has another way to get relief if the case is thrown out, the prejudice nonjoinder causes the defendant or the absent person, who could have avoided that prejudice, whether a protective court order could limit the damage, and whether the court can render an effective judgment without the missing party at all.
That balancing test gives judges room to let a case proceed even with a gap in the party list, rather than forcing dismissal whenever someone who arguably belongs in the suit can't be reached. It reflects a judgment call: joinder protects absent parties and defendants from inconsistent obligations, but it should not become a tool for one side to derail a case that could otherwise be decided on the merits.
Frequently Asked Questions
Who is a necessary party in a New York lawsuit?
A necessary party under CPLR 1001(a) is someone needed for the court to award complete relief, or someone who might be treated unfairly by a judgment issued without their side being heard.
What happens if a necessary party won't join as plaintiff?
CPLR 1001(a) lets the plaintiff name that person as a defendant instead, so the case can go forward without giving a reluctant party veto power over the lawsuit.
Can a New York case proceed without a necessary party?
Yes. Under CPLR 1001(b), if the court can't get jurisdiction over that person except through their own consent or appearance, the court may let the action proceed without them when justice requires it, after weighing the five factors listed in the rule.
What factors does a court weigh before excusing joinder under CPLR 1001?
The court looks at whether the plaintiff has another effective remedy if the case is dismissed, the prejudice to the defendant or the absent person, who could have avoided that prejudice, whether a protective order could help, and whether the court can still render an effective judgment.
What is the difference between CPLR 1001 and CPLR 1003?
CPLR 1001 defines who must be joined and when a court may excuse that joinder; CPLR 1003 sets the consequence, allowing dismissal without prejudice when a required party under 1001 is missing and the court has not excused it.
Advisory Committee Notes
It is believed that this section expresses the actual practice in the courts although it differs in language from the CPA provisions. The colorless and misleading expression “united in interest” is eliminated in favor of other language which closely follows that found in CPA § 193(1), and which may be traced to § 102 of the original Field code. The term “conditionally necessary” is also eliminated, although the new CPLR section does recognize that there are some persons who must be joined if it is possible to do so, but whose joinder is excused if jurisdiction over them cannot be obtained. See generally 12 NY Jud Council Rep 45, 163–191 (1946). Cf. CPA § 194 (“real party in interest”); Fed R Civ P 19(a) (“having a joint interest”).
The provision for making a person a defendant when he refuses to join as a plaintiff is found in § 194 of the CPA, being derived from the Field code which borrowed it from the chancery practice. The wording follows Federal rule 19(a).
Subd (a) is, of course, subject to the provisions of subdivision (b) and to the provisions of § 1005 governing class actions.
Subd (b) classifies the persons described in subdivision (a) into those who are indispensable and whose absence will result in the dismissal of the action, and those who are not indispensable and whose joinder is excused if jurisdiction over them cannot be obtained. Cf. Fed R Civ P 19(b); CPA § 193(2). This subdivision is principally devoted to the case of the necessary party who is not indispensable. It provides that he must be brought in if he is subject to the jurisdiction of the court, but that if he cannot be brought in, the court in its discretion can proceed without him. This is essentially the same provision which is found in CPA § 193(2) which excuses the joinder if the person cannot be “brought in without undue delay.” A new feature of the section is the enumeration of five criteria for determining whether a person is so important as a party that the action must be dismissed if he is not joined. A germ of the idea may be present in CPA § 193(1), where there is reference to an absentee who “would be inequitably affected by the judgment.” This language is borrowed from the Iowa rule. 12 NY Jud Council Rep 168, 178 n 57 (1946). The considerations enumerated are those emphasized in the case law, which, on analysis, indicates that the subject defies definitive statement and that decision must rest in the sound discretion of the court. The fundamental philosophy is that indispensability should be determined in the light of all the factors and interests involved including those of the court, and that there is no single certain criterion for determining whether a person is an indispensable party. Not only should the effect of nonjoinder be considered, but also the question of who might avoid or minimize its consequences. The reference in (5) of subd (b) is to the possibility that a judgment rendered in the absence of some person would, on account of that absence, be so hollow or inconclusive that it would be a waste of the court’s and the parties’ time to proceed with the litigation.
The wording of the subdivision permits the court to postpone the determination of indispensability until the trial or judgment stage is reached. This may be desirable in cases where it cannot be determined at a preliminary stage whether it is safe or reasonable to enter a judgment in the absence of some person who may have an interest. Of course, no one is legally bound by a judgment unless he is a party to the action or is represented by a party, but a dispensable person is sometimes affected by a judgment in some practical way without being legally bound by it.
Provisions, like those of Federal rule 19(b), excusing the joinder if it would deprive the court of its jurisdiction, are not included, since they are significant only in connection with the diversity jurisdiction of the Federal courts and have no place in state procedure. A provision like that of Federal rule 19(b) which speaks of persons “subject to the jurisdiction of the court as to both service of process and venue” has been omitted in view of proposed § 502 of the article on venue. Cf. CPA § 193.
Amendment History
Add, L 1962, ch 308, eff Sept 1, 1963; amd, L 1963, ch 532, § 9, 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 1001 New Yorknecessary party New York lawsuitindispensable party CPLRrequired joinder of parties New Yorkwho must be joined in a lawsuit New Yorkcompulsory joinder CPLR 1001party joinder rules New York civil procedure