Interrogatories are written questions you send to your opponent (and your opponent sends to you) in a lawsuit. They're one of several ways you'll collect evidence to use in your case. You're required to answer each interrogatory in writing and under oath by a certain deadline. Because you're answering under oath, and because your answers are likely to lead to other questions, you should take care when answering interrogatories.
We'll explain what interrogatories are and how they work, with examples of interrogatory questions and answers so you can see what they look like.
Interrogatories are sent and answered during a process called "discovery," which is the part of a lawsuit where the parties gather evidence to prepare for trial. Let's find out what discovery is, the rules that control it, and what can be discovered.
Discovery is the part of a civil lawsuit where each party (the "plaintiff" who has filed the lawsuit and the "defendant" who is being sued) learns about the claims, defenses, and facts known to, or being relied on, by the other parties. It begins shortly after the lawsuit starts.
A lawsuit might take from six months to more than a year to finish in the trial court, and most of that time will be taken up by discovery.
Every state (and the federal court system) has detailed written "rules of civil procedure" which—among other things—identify the allowable discovery methods and describe when and how discovery can happen. (Here's an electronic version of the 2023 federal rules of civil procedure to give you an example. Be sure you check the rules for your state if your case is in state court.)
Unfortunately, there's no simple answer to this question. The best we can do here is lay out a few basic, general rules. If you're in a lawsuit and are fighting with the other side about what's discoverable, you should think about hiring a lawyer to assist you.
Here are the most basic requirements for something to be "discoverable."
Material is relevant if it tends to make some fact significant to the case more or less likely to be true. Let's assume, for example, that in a car wreck case, the plaintiff claims the defendant was drunk at the time of the collision. The defendant denies being drunk.
The number and type of alcoholic drinks the defendant had in the hours leading up to the wreck clearly would be relevant, and a proper discovery subject. On the other hand, whether the defendant was carrying on an extramarital affair with a co-worker around the time of the wreck likely isn't relevant.
Some evidence is "privileged," meaning that, as a general rule, it can't be discovered or used at trial. Whether a privilege exists and, if so, the scope of the privilege, are questions of state law. Here are a couple of examples.
The attorney-client privilege protects communications between attorneys and their clients relating to the subject matter of the representation. In a car wreck case, conversations between an attorney and a client about the accident likely would be privileged. Conversations about the city's professional football team would not be (but they might not be relevant).
The physician-patient privilege protects communications between doctors and their patients relating to the diagnosis, treatment, or cure of any medical condition. Note, though, that a personal injury plaintiff claiming some physical or emotional injury can be required to waive this privilege to the extent necessary to make those claims.
Interrogatories are individual, separately-numbered written questions. They ask for information about a lawsuit, including:
While they're referred to as questions, there's no rule that requires interrogatories to be phrased in question form.
Interrogatories can be sent at any time during discovery. As we'll see, interrogatories are particularly useful for gathering general and background information about the parties and the case. As a result, they're usually among the first discovery requests the parties exchange once discovery begins.
There's another reason why interrogatories are sent early in discovery: Interrogatory answers often suggest topics for more questions later in discovery. For instance, suppose that in a car accident case, the defendant was taking a medication that might produce drowsiness. Medical information like that is something a well-drafted interrogatory would discover.
An interrogatory can lead to the plaintiff finding out more with additional discovery, like a deposition. In a deposition, a party (or more likely, a party's attorney) asks a "deponent" (the party or witness being questioned under oath) verbal questions. The questions and answers are recorded by a court reporter. Because they're face-to-face, depositions can be more spontaneous and allow for more detailed follow-up questions.
To continue with our medication example, in a deposition the plaintiff's lawyer might ask:
Federal and state rules of civil procedure limit the number of interrogatories a party can send. In federal court, for example, a party can't send more than 25 interrogatories without the recipient's or the court's permission. If an interrogatory is divided into subparts (for example, 3.a., 3.b., and 3.c.), each subpart is treated as a separate interrogatory. (See, e.g., Fed. R. Civ. Proc. 33(a)(1)(2023).)
A party who receives interrogatories must—as a general rule—answer each interrogatory fully, in writing, and under oath. Because they are made under oath, untruthful answers can subject the answering party to penalties for perjury.
Here are the rules of thumb for answering interrogatories:
The answer deadline varies, but 30 days is typical. Check your state's rules of civil procedure for specifics. Within limits set by the court, the parties can agree to extend the answer deadline, which is a common practice. The court also can grant an extension of time to answer.
What if an interrogatory asks for information that's outside the scope of discovery? Suppose, for instance, that an interrogatory asks the plaintiff about the substance of conversations the plaintiff had with others about the automobile accident that's the subject of the lawsuit. Some of those conversations—specifically, conversations the plaintiff had with their attorney—likely would be protected by the attorney-client privilege.
The correct response is to "object" to the interrogatory and to state the specific reason for objecting. Once the objection is fully stated, answer the interrogatory to the extent possible without disclosing objectionable information. (Here's another good time to note that you would ideally have a lawyer, who in this instance would help you answer and object to the questions.)
Here's how that would look:
"Plaintiff objects to Interrogatory 12 because it seeks information protected by the attorney-client privilege. Without waiving this objection, plaintiff states that plaintiff has discussed the auto accident with the following persons:
Two final points. First, your answers and objections need to comply with the rules of procedure in your state. Be sure you're familiar with those rules.
Second, if you have reason to object to an interrogatory but you fail to do so, the court can treat your objection as "waived." This means you've given up the right to object and must answer the interrogatory even if it asks for something improper.
Again, having a lawyer is often critical during litigation. Even if you don't have questions about how to answer or object to interrogatories (or other discovery), consider hiring experienced legal counsel to help.
Here are some sample car accident interrogatories and answers. These are questions likely to be asked by both parties, plaintiff and defendant.
ANSWER: I have lived at:
ANSWER: I am married to Jane Doe, who lives at 215 Maple Street, Smalltown, OH 55515. This is my only marriage.
ANSWER: I have two children, both by birth:
ANSWER: The people who have lived with me during the past 10 years are:
ANSWER: I have never pled guilty or no contest to, or been convicted of, a felony or misdemeanor.
ANSWER: I was cited by the City of Smalltown, OH in August 2018, for making an unlawful right-hand turn on a red light. I pled guilty and paid a fine.
ANSWER: I am not required to wear glasses or contact lenses while driving a motor vehicle.
ANSWER: I attended:
ANSWER: During the past 10 years I have worked at West Opolis Chevrolet, 370 South Avenue, West Opolis, OH 55511. My immediate supervisor is Karen Coe. I am an auto mechanic and my duties include repairing automobiles.
ANSWER: I have not been involved as a driver in any motor vehicle accident other than the accident which is the subject of this suit within the past 10 years.
ANSWER: James Doe, address listed above, no phone, my son, was the only passenger in my motor vehicle at the time of the accident.
ANSWER: I was driving from our home to the West Opolis Youth Sports Complex.
ANSWER: The persons who, to my knowledge, claim to have witnessed the accident, include:
OBJECTION: I object to this interrogatory because it asks for information protected by the attorney-client privilege.
ANSWER: Without waiving my objection, I have spoken to:
ANSWER: I did not drink any alcoholic beverages within the 24-hour period prior to the accident.
These sample interrogatories aren't intended to be a complete set. Each side would have more questions. For example, here are some additional topics the defendant would cover with the plaintiff:
If these questions sound very personal and intrusive, it's because they are. When a plaintiff sues for personal injuries, the plaintiff's medical history—usually including any history of mental or emotional issues—is at issue. The court will prevent the parties from harassing one another or getting into irrelevant or improper matters, but that leaves a lot of room for inquiry.
Outside of a trial, discovery can be one of the most contentious and confrontational times in a lawsuit. The parties often disagree about what's discoverable, and disagreements can be heated.
And while answering interrogatories—and writing ones of your own—might seem boring and tedious, a great deal is at stake. Your claim might depend on what evidence you collect and disclose.
An experienced personal injury attorney is used to the give-and-take of discovery and knows how to write and answer interrogatories in ways that best protect your interests and strengthen your claim or defense. (Learn about how to find an attorney.)