A CCP 170.6 peremptory challenge lets any party or attorney in a California civil or criminal case remove an assigned judge, court commissioner, or referee by filing a sworn statement that the judicial officer is prejudiced. You do not have to prove bias, describe any conduct, or attach evidence. If the declaration is in proper form and filed on time, disqualification is automatic and the case is reassigned without a hearing.
The catch is timing. Each side gets one peremptory challenge per case, and the filing window is short and unforgiving. Miss it and the right is gone for that judicial officer, permanently.
Filing Deadlines by Assignment Type
The deadline depends entirely on how the judge came to be on your case. Read this section carefully before doing anything else.
All-Purpose (Direct Calendar) Assignment
When one judge is assigned to handle a case from start to finish, a civil litigant has 15 days after receiving notice of the assignment to file the challenge, or 15 days after their first appearance in the case if the assignment was made before they appeared. In a criminal case, the equivalent window is 10 days, not 15.
Master Calendar Assignment
When a case is sent out for trial from a master calendar, the challenge must be presented to the judge supervising the master calendar no later than the moment the case is assigned for trial. There is no multi-day grace period. As soon as you learn which trial judge you are getting, you either challenge or you lose the option.
Assignment for a Specific Hearing
If a different judge is assigned to hear a particular motion or hearing and you know that judge’s identity at least 10 days before the hearing date, the challenge must be filed at least five days before the hearing. If the identity is not known that far in advance, the challenge must be made before the hearing begins.
Single-Judge Courts
In a court with only one judge, a party challenging that judge has 30 days from their first appearance in the case.
The Absolute Cutoff
No matter which deadline applies, no judge will entertain a 170.6 motion once the first juror’s name is drawn. In a bench trial, the cutoff is whichever comes first: the plaintiff’s opening statement, the swearing of the first witness, or the introduction of any evidence.
What the Challenge Has to Say
The core of the motion is a declaration or affidavit made under penalty of perjury. There is no statewide Judicial Council form for a 170.6 challenge. Individual courts publish their own local versions. The Los Angeles Superior Court, for example, uses form LACIV 015. Check with your courthouse clerk or the court’s website for the local form; if none exists, a written motion containing the statutory language will do.
Whether you use a local form or draft your own, the motion must contain:
- The case caption exactly as it appears on other filings, including the case number.
- The department where the case is assigned or being heard.
- The full name and title of the judge, commissioner, or referee being challenged. A wrong name is a common reason for rejection at the clerk’s window.
- A statement, substantially in the language of the statute, that the judicial officer is prejudiced against the party or attorney or their interest, so that the party or attorney cannot, or believes they cannot, have a fair and impartial trial or hearing.
- The party’s or attorney’s signature under penalty of perjury. If the statement is made orally in open court, it must be given under oath.
You do not describe what the judge did. You do not cite rulings. You do not attach exhibits. A conclusory sworn statement of belief is exactly what the statute contemplates.
How to File and Serve It
You have three ways to present the motion: a written filing at the clerk’s office, electronic filing where the court accepts it, or an oral statement under oath in open court. The oral option matters when an assignment happens on the spot and there is no time to prepare paperwork. An oral challenge must cover the same content a written affidavit would: the judicial officer’s name, the case, and the sworn assertion of prejudice.
For a written filing, submit it through whatever method your courthouse uses, at the clerk’s window or through the court’s e-filing portal. You are responsible for serving a copy on every other party so they know reassignment is coming.
The motion is presented to the assigned judge in an all-purpose case, to the presiding judge otherwise, or to the supervising judge in a master calendar court. The challenged judge does not decide whether the challenge has merit. If the paperwork is right and the deadline was met, that judge is off the case.
What Happens Next
A properly filed challenge disqualifies the judge “without any further act or proof,” in the words of the statute. A master calendar court’s supervising judge reassigns the case to another judicial officer. Elsewhere, the case moves to another judge in the same courthouse. If no other judicial officer is available, which can happen in smaller or rural courts, the Chair of the Judicial Council assigns one from another court “as promptly as possible.”
Earlier rulings generally survive. The statute expressly provides that a judge’s participation in pretrial conferences, hearings, or motions that did not involve contested fact issues on the merits does not block a later 170.6 challenge and does not automatically wipe out those earlier rulings. The new judge picks up where the prior one left off.
One Challenge Per Side
Any party or attorney in a civil or criminal action or special proceeding can file, and the statute covers superior court judges, court commissioners, and referees. The limit is strict: one peremptory challenge per side per case. Multiple plaintiffs share one; multiple defendants share one. This prevents parties from cycling through every judge in the courthouse.
A narrow exception applies when parties on the same side have “substantially diverse interests,” meaning genuinely conflicting legal positions, not just separate attorneys. Courts look for separate legal theories or competing claims among co-parties, not the fact that different lawyers appeared.
Public agencies can use 170.6 systematically. A district attorney’s office or public defender’s office can challenge the same judge across many cases, creating what functions as a blanket disqualification. The California Supreme Court upheld the practice in Solberg v. Superior Court (1977).
Why Challenges Get Rejected
Because disqualification is meant to be automatic, denials almost always come down to procedure rather than substance:
- Late filing. Missing the applicable deadline waives the right, and courts have no discretion to extend it.
- More than one challenge per side. If someone on your side already used it, yours will be rejected unless you can establish substantially diverse interests.
- Filing after trial has started. Once jury selection begins, a witness is sworn, or evidence comes in, the door is closed.
- A defective declaration. Missing statutory language, an unsigned or improperly sworn statement, or the wrong judicial officer’s name can all sink the filing. Some courts allow a corrected refiling if the deadline has not passed, but relying on that is risky.
- Aiming at a hearing already underway. For non-trial hearings, the motion has to be made before the hearing commences.
A denial on procedural grounds can sometimes be reviewed by writ of mandate, but appellate courts rarely disturb these rulings unless the trial court clearly misapplied the deadline.
When a Peremptory Challenge Is Not the Right Tool
If the judge has a concrete conflict, such as a financial interest in the case, a family relationship with a party or lawyer, prior involvement as an attorney in the same matter, or receipt of campaign contributions exceeding $1,500 from a party or lawyer in the proceeding, the appropriate motion is a for-cause disqualification under CCP 170.1. That path requires factual support and a ruling by the judge, but it is not subject to the one-per-side limit that governs 170.6. Most litigants who simply want a different judge reach for 170.6 because it is faster and does not require confronting the judge with specific allegations. The tradeoff is that you only get to use it once.