Check who the judge is the day an employment lawsuit is assigned. California lets each side remove one assigned judge without proving bias, through a peremptory challenge under Code of Civil Procedure section 170.6. The challenge is a sworn statement that the judge is prejudiced, and if it’s timely and in the right form, the court reassigns the case. The window is short, and an employer and the managers sued with it share a single challenge.
What does a 170.6 challenge do?
It removes the judge without a hearing on bias. Section 170.6(a)(1) says a superior court judge, commissioner, or referee “shall not try a civil or criminal action or special proceeding of any kind or character nor hear any matter therein that involves a contested issue of law or fact” when it’s established under the section that the judge “is prejudiced against a party or attorney or the interest of a party or attorney appearing in the action or proceeding.”
The showing is a sworn statement, not evidence. Under section 170.6(a)(2), a party or attorney “may establish this prejudice by an oral or written motion without prior notice supported by affidavit or declaration under penalty of perjury, or an oral statement under oath,” that the party or attorney “cannot, or believes that he or she cannot, have a fair and impartial trial or hearing” before that judge. The statute even supplies the form of the affidavit.
Once the motion is properly made, section 170.6(a)(4) says that “thereupon and without any further act or proof,” another judge is assigned. The party making the motion also has to “serve notice on all parties no later than five days after making the motion,” under subdivision (a)(3).
When does the challenge have to be filed?
It depends on how the case is assigned. For a civil case assigned to one judge for all purposes, section 170.6(a)(2) says the motion “shall be made to the assigned judge or to the presiding judge by a party within 15 days after notice of the all purpose assignment, or if the party has not yet appeared in the action, then within 15 days after the appearance.”
That second clause matters for a newly served employer. If the company hasn’t appeared yet, the clock runs from its first appearance, usually its first filing in the case, such as an answer or demurrer. A company that files its first paper without knowing who the judge is can lose the challenge before anyone has thought about it.
Other timing rules apply when the case isn’t assigned for all purposes. If the judge assigned to try a cause or hear a matter is known at least 10 days before the trial or hearing, the motion “shall be made at least 5 days before that date,” and in a master calendar court it “shall be made to the judge supervising the master calendar not later than the time the cause is assigned for trial,” under the same subdivision. The motion can’t be made at all once trial has started.
Earlier activity by the judge doesn’t always end the right. The statute says a judge’s role in “a pretrial conference or other hearing, proceeding, or motion prior to trial, and not involving a determination of contested fact issues relating to the merits, shall not preclude the later making of the motion” at the proper time.
Who shares the challenge?
Everyone on the same side. Section 170.6(a)(4) says “no party or attorney shall be permitted to make more than one such motion in any one action or special proceeding,” and when there is more than one defendant, “only one motion for each side may be made in any one action or special proceeding.”
Employment lawsuits often name the company and one or more individual managers, and sometimes a staffing agency or a related entity. They’re all on one side for this purpose. If a separately represented manager files a challenge first, the company may have lost its own chance to choose. Coordinating with every co-defendant’s counsel in the first days of the case avoids that.
The plaintiff has a separate challenge. If the employee uses it and a new judge is assigned, the defense side still has its own. There’s also a narrow second chance under the statute after an appeal: a motion may be made “following reversal on appeal of a trial court’s final judgment, if the trial judge in the prior proceeding is assigned to conduct a new trial on the matter.”
How is this different from a challenge for cause?
A challenge for cause requires proof. Section 170.6 is cumulative, and subdivision (b) says it doesn’t “affect or limit Section 170” or the place-of-trial provisions. A party that believes a judge should be disqualified for a specific reason can file a verified statement under section 170.3(c)(1) “setting forth the facts constituting the grounds for disqualification of the judge,” and it “shall be presented at the earliest practicable opportunity after discovery of the facts constituting the ground for disqualification.”
The two tools work differently. A peremptory challenge is fast and certain if it’s timely, but it’s spent once it’s used. A for-cause challenge is decided by another judge, and the company has to prove the grounds. Most employers will only ever need the peremptory challenge, and they’ll need to decide quickly whether to use it.
How do the rules compare?
| Issue | Peremptory challenge (CCP § 170.6) | Challenge for cause (CCP § 170.3) |
|---|---|---|
| What has to be shown | A sworn statement of prejudice | Facts that establish a ground for disqualification |
| Timing | Short statutory deadlines tied to the assignment or hearing | The earliest practicable opportunity after learning the facts |
| Who decides | Granted on a timely, proper motion | Another judge, if the challenged judge doesn’t consent |
| Shared with co-defendants | Yes, one motion for the defense side | Each party may file |
What should the company do in the first days of an employment lawsuit?
- Preserve the records the case will turn on under a litigation hold, including the personnel file, pay and time records, emails and texts, and the policies in effect at the time.
- Calendar the response deadline on the summons and the 170.6 deadline from the notice of assignment or the company’s first appearance, and notify the EPLI carrier and check for an arbitration agreement.
- Identify every co-defendant and its counsel, agree on who decides whether to use the defense side’s single challenge, and make sure no one takes action against the plaintiff that could look like retaliation.
- Pull the court’s notice of assignment and the department’s information so the decision about the judge is made before the company files anything.
- Talk to a lawyer before the first appearance, because the decision about the judge is easiest to make before the window starts running.
Early procedural choices like this one are part of trial-court strategy for employers in employment cases, which the firm’s employment defense page describes.
170.6 questions from California employers
Does the company have to say why it’s challenging the judge?
No reason beyond the sworn statement is required. The statute’s form affidavit says only that the judge “is prejudiced against the party (or his or her attorney) or the interest of the party (or his or her attorney)” so that the affiant can’t have a fair and impartial trial, according to section 170.6(a)(6). The motion shouldn’t argue the judge’s record, and the papers should stay short.
Will a 170.6 challenge delay the case?
Usually not much. Section 170.6(a)(5) says that unless it’s needed for the court’s convenience or good cause is shown, “a continuance of the trial or hearing shall not be granted by reason of the making of a motion under this section.” The case moves to a new department, which manages the schedule from there.
Can the company use the challenge against the judge assigned after the plaintiff’s challenge?
Yes, if the defense side hasn’t used its own challenge and the motion is timely. The rule is one per side. The new assignment creates a new decision point, and the company should calendar the deadline from the notice of reassignment just as it did for the first one.
What if the case is in arbitration?
Section 170.6 applies to superior court judicial officers, including commissioners and referees. It doesn’t govern the choice of an arbitrator, which follows the arbitration agreement and the provider’s rules. If a court proceeding continues alongside the arbitration, such as a petition to compel or a stayed claim, the 170.6 rules apply to that proceeding.
If your company has just been served with an employment lawsuit
If your company has been sued by a current or former employee, the first weeks decide some things that can’t be revisited later, including who will hear the case. Rosenberger + Kawabata represents employers defending employment lawsuits and claims through its business litigation practice, including claims involving wrongful termination and discrimination in superior court. Contact Rosenberger + Kawabata online for a confidential consultation, or call (310) 894-6921.
Sources
The statutes are Code of Civil Procedure section 170.6, as last amended by Assembly Bill 1894 (Stats. 2010, ch. 131), and Code of Civil Procedure section 170.3.
This post is general information about California and federal employment law as of November 7, 2026. It is not legal advice, and reading it does not create an attorney-client relationship. Employment statutes, regulations, and court decisions change often, and the outcome of any claim depends on its facts. Past results do not guarantee future outcomes.