Legal Memorandum: Supplemental and Amended Complaints

Issue: Under California law, under what circumstances may a plaintiff successfully bring an ex parte application to file a supplemental complaint as opposed to an amended complaint?

Area of Law: Litigation & Procedure
Keywords: Supplemental complaint; Amended complaint; Separate pleadings
Jurisdiction: California
Cited Cases: 91 P. 593; 69 Cal. Rptr. 719; 263 Cal. App. 2d 430; 185 Cal. Rptr. 848; 182 P. 67; 45 Cal. App. 3d 644; 40 Cal. App. 733; 151 Cal. 732
Cited Statutes: Cal. Civ. Proc. Code § 464;
Date: 02/01/2001

           A supplemental complaint is permitted by Cal. Civ. Proc. Code § 464 for the sole purpose of "alleging facts material to the case occurring after the former complaint."  (emphasis added).  The supplemental complaint does not take the place of the former complaint; instead, the two are separate pleadings with the supplemental complaint serving to bring before the court matters which have occurred after filing the prior pleading: 

Appellant fails to note the distinction between a complaint (or one as amended) and a supplemental complaint.  They are to be considered as separate pleadings, the office of the supplemental complaint being merely to bring to the notice of the court, and the opposite party, matters which occurred after the commencement of the action, and which do, or may, affect the rights asserted, and the rule asked in the action, as originally instituted.


Conlin v. Southern Pac. Ry. (1919) 40 Cal. App. 733, 182 P. 67, 70, review denied (June 19, 1919).  The original and amended complaint set forth all the plaintiff’s theories of liability as they exist at the commencement of the suit, while the supplemental complaint merely updates the court on post-filing factual developments:

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