In one sentenceRule 19 requires a court to join any person whose absence would prevent complete relief or put that person’s own interests at risk, and if that person cannot be joined, directs the court to weigh prejudice, alternative remedies, and equity in deciding whether to proceed without them or dismiss the case.
1A person required to be made a party. A person who is subject to service of process and whose joinder will not deprive the court of subject-matter jurisdiction must be joined as a party if:
Ain that person’s absence, the court cannot accord complete relief among existing parties; or
Bthat person claims an interest relating to the subject of the action and is so situated that disposing of the action in the person’s absence may:
ias a practical matter impair or impede the person’s ability to protect the interest; or
iileave an existing party subject to a substantial risk of incurring double, multiple, or otherwise inconsistent obligations because of the interest.
2Joinder by court order. If a person required to be made a party has not been joined, the court must order that the person be made a party. A person who refuses to join as a plaintiff may be made either a defendant or, in a proper case, an involuntary plaintiff.
3Venue. If a joined party objects to venue and the joinder would make venue improper, the court must dismiss that party.
bWhen joinder is not feasible. If a person required to be joined if feasible cannot be joined, the court must determine whether, in equity and good conscience, the action should proceed among the existing parties or should be dismissed. The factors for the court to consider include:
1the extent to which a judgment rendered in the person’s absence might prejudice that person or the existing parties;
2the extent to which any prejudice could be lessened or avoided by:
Aprotective provisions in the judgment;
Bshaping the relief; or
Cother measures;
3whether a judgment rendered in the person’s absence would be adequate; and
4whether the plaintiff would have an adequate remedy if the action were dismissed for nonjoinder.
cPleading the reasons for nonjoinder. When asserting a claim for relief, a party must state:
1the name, if known, of any person required to be joined if feasible who is not joined; and
2the reasons for not joining that person.
dException of class actions. This rule is subject to Rule 23.
Amendment History
Promulgated by R-16-0010, effective January 1, 2017.
Plain-English Summary
Rule 19 identifies people who belong in a lawsuit even though no one has named them. A person who can be served and whose joinder would not strip the court of jurisdiction must be added as a party if, without that person, the court cannot grant complete relief to the parties already in the case, or if leaving that person out could impair their ability to protect their own interest or expose an existing party to double or inconsistent obligations. If such a person refuses to join as a plaintiff, the rule lets the court realign them as a defendant or an involuntary plaintiff instead, and a joined party who has a valid venue objection must be dismissed rather than forced to litigate in the wrong court.
Sometimes the person who should be joined cannot be — perhaps they cannot be served, or joining them would destroy the court's jurisdiction. When that happens, the court weighs whether to proceed among the existing parties or dismiss the case entirely, looking at how much a judgment might prejudice the absent person or the current parties, whether that prejudice can be softened through protective terms in the judgment or by shaping the relief differently, whether a judgment issued without the absent person would still be adequate, and whether the plaintiff would have anywhere else to turn if the case were dismissed.
Any complaint that names a claim must also flag the problem: if a person who should be joined is not, the pleading has to state that person's name, if known, and explain why they were left out. The rule yields to Rule 23, so it does not override how class actions handle absent class members.
Frequently Asked Questions
When must a court order someone joined as a party who was not originally named?
When that person’s absence would prevent complete relief among the existing parties, or would risk impairing that person’s interests or subjecting existing parties to inconsistent obligations.
What happens if a person who should be joined cannot be brought into the case?
The court weighs prejudice to the absent person and existing parties, whether that prejudice can be reduced, whether a judgment would still be adequate, and whether the plaintiff has another remedy, then decides whether to proceed or dismiss.
Can a court add someone as a plaintiff without their consent?
Yes, if that person refuses to join voluntarily, the court may realign them as a defendant or an involuntary plaintiff instead.
Does Rule 19 apply to class actions?
No, class actions are governed separately under Rule 23.
Source & verification. The rule text and History are reproduced verbatim from the
official Arizona Rules of Civil Procedure (Ariz. R. Civ. P. 19). Prescribed by the Supreme Court of Arizona (Ariz. Const. art. 6, § 5). The plain-English summary is original and written by us. Last verified July 1, 2026. ·
Official source
Also known as:required joinderindispensable partynecessary partyjoinder if feasible