What is a UD-100? The unlawful detainer complaint, explained

Form

UD-100

Official name

Complaint, Unlawful Detainer

Who gives it to you

Served on you with the SUM-130 summons by the landlord's process server

The clock it starts

Same deadline as the summons: 10 court days from service to file a response

Version shown here

Rev. July 1, 2026, optional form

What to do if you are served a UD-100

1. Find the notice attached as an exhibit. Item 9 of the complaint describes the notice the case is built on, and a copy is supposed to be attached. Compare the attached notice with what you actually received. Differences in dates, amounts, or wording matter.
2. Check every box the landlord checked. The complaint is a checkbox form. The type of notice, the date it expired, the way it was served, the rent claimed, and whether daily damages are requested are each a factual claim you can dispute in your answer.
3. Look at the caption and the parties. Confirm the property address, the names of every defendant, and whether the box for Does 1 to 10 or a Prejudgment Claim is checked. Adults living in the home who are not named have their own options.
4. Prepare and file your response. For most tenants that is the UD-105 answer, filed at the court named on the summons with the fee or a fee waiver, and served on the landlord's attorney. Call us with the packet in hand and we will tell you what fits.

The UD-100, Complaint, Unlawful Detainer, is the landlord’s side of the story in court form. Where the SUM-130 summons tells you that you are being sued and how long you have to respond, the UD-100 tells you why. It is an optional Judicial Council form, but nearly every California landlord and eviction attorney uses it because the court’s own system is built around it.

How the complaint is laid out

The first page carries the caption: the landlord as plaintiff, the tenants as defendants, the court, and the case number. Under it the form asks a series of numbered questions with checkboxes. The ones that decide most cases are:

• Item 6, the tenancy. When it started, the rent amount, when rent is due, and whether the agreement was written or oral. The lease is supposed to be attached as Exhibit 1.
• Item 9, the notice. Which kind of notice was served, on which defendants, the date the notice period expired, and how it was served. The notice itself is supposed to be attached as Exhibit 2.
• Item 12, past due rent. The amount the landlord says was demanded in a 3-day notice to pay rent or quit.
• Item 13, damages. The daily rental value the landlord will ask for from the day the notice expired until judgment.
• Item 17, what the landlord wants. Possession of the premises, costs, past due rent, damages, and sometimes attorney fees if the lease allows them.

The last page is the verification, where the landlord or the landlord’s agent swears under penalty of perjury that the contents are true. Because the complaint is verified, your answer has to be verified too, which is part of why the UD-105 form matters.

What to check first

Start with the attached notice, not the complaint. The complaint can only be as good as the notice it is built on. Compare the exhibit with the copy you were given: the amount demanded, the dates, the names, the property description, the payment instructions, and the way it says it was delivered. A notice that demands more than the rent actually owed, bundles in late fees or utilities, or was served the wrong way is challenged in California courtrooms every day.

Then check the complaint against the notice. If item 9 says the notice was personally served on a date you know you were not home, or the expiration date does not add up, those are facts you can deny in your answer.

What is served with it

The UD-100 is served with the SUM-130 summons and the UD-101 Plaintiff’s Mandatory Cover Sheet and Supplemental Allegations. If the landlord wants to bind adults who are not named in the complaint, a CP10.5 Prejudgment Claim of Right to Possession will be in the packet as well. Keep everything together, including the envelope if it came by mail, because the proof of service on the summons is what the court uses to count your deadline.

How to respond

The usual response is the UD-105 Answer, Unlawful Detainer. It lets you deny the landlord’s allegations and raise affirmative defenses such as a defective notice, payment or tender of rent, breach of the warranty of habitability, retaliation, or a landlord who failed to follow a required procedure. If the complaint has a legal problem on its face, a demurrer can be filed instead of an answer, and if service was improper a motion to quash comes first. Each of those has to be filed inside the response window printed on the summons.

We read the whole packet with you, identify what fits, prepare the response, and file it before the deadline. The consultation is free, and you can start it by reading us item 9 over the phone.

This website provides general information about the California eviction process and is not legal advice. Court forms are reproduced from the Judicial Council of California; confirm you are using the current revision before filing.