In one sentenceRule 13 requires a party to raise any counterclaim arising from the same transaction as the opposing party's claim or lose it, allows unrelated counterclaims and crossclaims against a coparty on a permissive basis, and lets a court enter separate judgment on a counterclaim or crossclaim even while other claims remain pending.
1Generally. A pleading must state as a counterclaim any claim that—at the time of its service—the pleader has against an opposing party if the claim:
Aarises out of the transaction or occurrence that is the subject matter of the opposing party’s claim; and
Bdoes not require adding another party over whom the court cannot acquire jurisdiction.
2Exceptions. The pleader need not state the claim if:
Awhen the action was commenced, the claim was the subject of another pending action; or
Bthe opposing party sued on its claim by attachment or other process that did not establish personal jurisdiction over the pleader on that claim, and the pleader does not assert any counterclaim under this rule.
bPermissive counterclaim. A pleading may state as a counterclaim against an opposing party any claim that is not compulsory.
cRelief sought in a counterclaim. A counterclaim need not diminish or defeat the recovery sought by the opposing party. It may request relief that exceeds in amount or differs in kind from the relief sought by the opposing party.
dCounterclaim against the state. These rules do not expand the right to assert a counterclaim—or to claim a credit—against the State of Arizona or one of its officers or agencies.
eCounterclaim maturing or acquired after pleading. The court may permit a party to file a supplemental pleading asserting a counterclaim that matured or was acquired by the party after serving an earlier pleading.
1Generally. A party may state as a crossclaim any claim against a coparty if the claim arises out of the same transaction, occurrence, or event that is the subject matter of the original action or of a counterclaim, or if the claim relates to any property that is the subject matter of the original action. The crossclaim may include a claim that the coparty is or may be liable to the cross-claimant for all or part of a claim asserted in the action against the cross-claimant.
2When codefendants must present crossclaims. A defendant’s crossclaim against a codefendant must be stated when the defendant files an answer or other response to the complaint or counterclaim, unless an amendment is later allowed under Rule 15(a).
gJoining additional parties. Rules 19 and 20 govern the addition of a person as a party to a counterclaim or crossclaim.
hSeparate trials; separate judgments. If the court orders separate trials under Rule 42(b), it may enter judgment on a counterclaim or crossclaim under Rule 54(b) when it has jurisdiction to do so, even if the opposing party’s claims have been dismissed or otherwise resolved.
Amendment History
Promulgated by R-16-0010, effective January 1, 2017.
Plain-English Summary
If a party has a claim against an opposing party that grows out of the same transaction or occurrence as that party's claim, and doesn't require adding someone the court can't reach, the party must raise it as a counterclaim or lose it — with narrow exceptions for claims already pending in another action or claims against a party that only obtained jurisdiction through attachment. A party may also bring any other claim against an opposing party as a permissive counterclaim, even one unrelated to the original dispute, and that counterclaim doesn't need to reduce or offset what the opposing party is seeking.
These rules don't expand anyone's right to counterclaim, or claim a credit, against the State of Arizona or its officers and agencies beyond what already exists elsewhere. A court may also let a party add a counterclaim that matured or was acquired only after an earlier pleading was served.
A crossclaim works the same way but runs against a coparty rather than an opponent — it must arise from the same transaction, occurrence, or property at issue in the case, and can include a claim that the coparty is liable for part of what's being sought against the cross-claimant. A defendant's crossclaim against a codefendant must be raised when that defendant first answers or responds, unless a later amendment is allowed. Rules 19 and 20 control adding any new party needed for a counterclaim or crossclaim, and if the court orders separate trials, it may enter judgment on a counterclaim or crossclaim on its own even if the opposing party's claims are still being sorted out.
Frequently Asked Questions
When must a party raise a counterclaim or risk losing it?
When the claim arises out of the same transaction or occurrence as the opposing party's claim and doesn't require adding a party outside the court's reach.
Can a party bring a counterclaim unrelated to the plaintiff's claim?
Yes, as a permissive counterclaim, even if it doesn't offset or relate to the opposing party's claim.
What is a crossclaim, and when must it be raised?
A claim against a coparty arising from the same transaction, occurrence, or property at issue; a defendant's crossclaim against a codefendant must be raised in the answer unless a later amendment is allowed.
Can a court enter judgment on a counterclaim before the rest of the case is resolved?
Yes, if the court has ordered separate trials and has jurisdiction to do so, even while the opposing party's claims remain unresolved.
Source & verification. The rule text and History are reproduced verbatim from the
official Arizona Rules of Civil Procedure (Ariz. R. Civ. P. 13). 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:compulsory counterclaimpermissive counterclaimcrossclaim