Where a person files a cross-complaint as authorized by Section 428.10, he may unite with the cause of action asserted in the cross-complaint any other causes of action he has against any of the cross- defendants, other than the plaintiff in an eminent domain proceeding, whether or not such cross-defendant is already a party to the action.
§ 428.30.Action United With Action Asserted In Cross- Complaint
Title 6. Of the Pleadings In Civil Actions · Chapter 2. Pleadings Demanding Relief · Article 4. Cross-Complaints · Enacted 1971 · no amendments on record · Last verified July 28, 2026
In one sentenceSection 428.30 lets a party filing a cross-complaint unite it with any other causes of action that party has against any of the cross-defendants, other than the plaintiff in an eminent domain proceeding, whether or not the cross-defendant is already a party.
Full Text of § 428.30
Plain-English Summary
Section 428.30 extends the permissive-joinder logic of § 427.10 into the cross-complaint setting. Once a party files a cross-complaint authorized under § 428.10, that party may unite any other causes of action it has against any of the cross-defendants named in it, regardless of whether the cross-defendant was already a party to the action before the cross-complaint was filed.
The joinder is optional, matching § 427.10's approach to a plaintiff's own complaint: the cross-complainant is not required to bring every available claim against a given cross-defendant, only permitted to combine them in the same cross-complaint if it chooses.
One exception carries through from § 428.10(a): a cross-complainant cannot use this joinder mechanism to unite additional causes against the plaintiff in an eminent domain proceeding, consistent with the broader pattern in this title of treating the condemning agency's role in eminent domain differently from an ordinary civil plaintiff.
Frequently Asked Questions
Can I add unrelated claims against a cross-defendant to my cross-complaint?
Yes. Section 428.30 lets a party filing a cross-complaint unite any other causes of action it has against a cross-defendant with the cause of action already asserted in the cross-complaint.
Does the cross-defendant have to already be a party to the case?
No. Section 428.30 allows this joinder whether or not the cross-defendant is already a party to the action.
Is there any limit on which cross-defendants this applies to?
Yes. Section 428.30 excludes the plaintiff in an eminent domain proceeding from this joinder mechanism, consistent with § 428.10(a)'s similar limit.
Amendment History
Added by Stats. 1971, Ch. 244.
Source & verification. Section text is reproduced verbatim from
the Deering's California Codes Annotated / vLex. Enacted by the California Legislature.
Last verified July 28, 2026.
· Official source
Also known as: joining causes of action in a cross complaint californiauniting claims against cross defendant california