§ 2033.020.Admissions without leave of court; time to

This section answers the same timing question the chapter on interrogatories answers for that discovery method, applied here to requests for admission. A defendant faces no waiting period and may serve requests for admission on a party at any time once the action begins. A plaintiff faces a short buffer instead: requests may go out once 10 days have passed since the summons was served on, or the party appeared in the action, whichever comes first. That identical 10-day rule carries over to unlawful detainer actions and other summary proceedings to recover possession of real property, even though those cases move on a compressed schedule overall.

A plaintiff who cannot wait out the 10 days has a way around the rule. On a motion, which can be made with or without notice, the court may grant leave to serve requests for admission earlier on a showing of good cause. That option matters most where a case is heading to a quick trial date, or where a plaintiff needs to lock in an admission before evidence changes or disappears, situations where the standard 10-day buffer would eat into an already short window.