(a) The plaintiff and defendant, respectively, may be allowed, on motion, to make a supplemental complaint or answer, alleging facts material to the case occurring after the former complaint or answer.
§ 464.Supplemental Complaint Or Answer; Action Seeking Child Support
Title 6. Of the Pleadings In Civil Actions · Chapter 7. General Rules of Pleading · Last amended 1995 · Last verified July 28, 2026
In one sentenceSection 464 lets either party move to file a supplemental complaint or answer alleging facts arising after the original pleading, lets a child support or paternity supplemental complaint skip leave of court, and requires the clerk to issue a supplemental summons under § 412.10.
Full Text of § 464
(b) The plaintiff and defendant, or petitioner and respondent, may, in any action in which the support of children is an issue, file a supplemental complaint seeking a judgment or order of paternity or support for a child of the mother and father of the child whose paternity and support are already in issue before the court. A supplemental complaint for paternity or child support may be filed without leave of court either before or after final judgment in the underlying action.
Plain-English Summary
Facts do not stop happening once a complaint or answer is on file. Section 464(a) lets either party move for permission to file a supplemental pleading alleging facts material to the case that occurred after the original complaint or answer was filed.
Subdivision (b) carves out a specific, faster path for child support and paternity cases: a party may file a supplemental complaint seeking a judgment or order of paternity or support for a child of the same parents already before the court, without needing leave of court, and this can happen either before or after final judgment in the underlying action.
Once a supplemental complaint is filed, § 464(c) requires the clerk to issue an amended or supplemental summons under § 412.10, and that summons and the supplemental complaint must be served the same way an initial summons and complaint would be.
Frequently Asked Questions
Do I need the court’s permission to file a supplemental complaint over new facts?
Generally yes — § 464(a) requires a motion for a general supplemental complaint or answer. The exception is a child paternity or support supplemental complaint under § 464(b), which may be filed without leave of court.
What happens after a supplemental complaint is filed?
Section 464(c) requires the clerk to issue an amended or supplemental summons under § 412.10, which must then be served in the same manner as an initial summons.
Can a supplemental complaint for child support be filed after judgment?
Yes. Section 464(b) allows it either before or after final judgment in the underlying action.
Amendment History
Amended by Stats. 1994, Ch. 1269, Sec. 2.8. Effective January 1, 1995.
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: supplemental complaint californiasupplemental pleading new facts after filing