Short answer. Yes. Section 8 of Rule 11 requires that a compulsory counterclaim or cross-claim a defending party already has at the time they file their answer must be contained in that answer — it can't be held back and filed separately later without risking waiver.

What the law says

A compulsory counterclaim or a cross-claim that a defending party has at the time he or she files his or her answer shall be contained therein.

Rule 11, Section 8 — Existing counterclaim or cross. Read the full provision →

The mandatory timing for existing claims

Section 8 is direct: a compulsory counterclaim or a cross-claim that a defending party has at the time he or she files his or her answer shall be contained therein. The word 'shall' makes this mandatory rather than discretionary — a defendant cannot simply choose to sit on an existing counterclaim or cross-claim and raise it in a separate, later filing once they already have it in hand at the time the answer is due.

Why 'compulsory' matters here

This provision specifically addresses claims that already exist and are ripe when the answer is filed — as distinct from claims that mature or are acquired only later, which the following section of the same Rule addresses separately with a more permissive approach. The distinction turns on timing: was the claim already in hand at the moment the answer needed to be filed, or did it arise afterward? Section 8's mandatory language applies only to the first situation; a claim that had not yet accrued cannot realistically be pleaded, which is exactly why the rule needs the separate, later-arising-claim provision alongside it. The obligation binds every defending party who already holds a ripe claim at answer time, whether that party is an original defendant, a co-defendant asserting a cross-claim, or a third-party defendant — the timing requirement does not vary with who is doing the defending.

Practical consequence of not including it

A defendant preparing an answer needs to think, at that moment, about whatever claims they already have against the plaintiff arising from the same transaction, because Section 8 does not leave room to defer that decision. Failing to include an existing compulsory counterclaim in the answer risks losing the ability to raise it later, which is why lawyers typically treat the answer-drafting stage as the point to fully account for the client's own claims against the plaintiff, not just their defenses. Cross-claims against a co-defendant follow the same rule: if it already exists when the answer is filed, it belongs in that same pleading rather than in something filed afterward. Section 8 does not itself spell out the sanction for noncompliance — that consequence, generally described as waiver of the omitted claim, comes from the broader compulsory-counterclaim doctrine the Rules build around this timing requirement, not from any separate penalty clause within Section 8.

Related provisions

Note. Statute text quoted on this page is reproduced from the official enactment and is linked to the full provision. The explanation around it is general legal information from Vivas & Nobles Law Office, not legal advice. Whether it applies to your situation depends on facts only a lawyer reviewing them can assess.