Interrogatories in legal discovery are written questions that one party in a civil lawsuit sends to another party, which must be answered in writing and under oath. Federal rules cap them at 25 per party, and the receiving party has 30 days to respond. They are one of the main tools lawyers use during discovery to pin down facts and lock the other side into a position before trial.
Who Can Send and Receive Them
Any party in a lawsuit can send interrogatories to any other party. Plaintiffs can send them to defendants, defendants to plaintiffs, and co-defendants to each other. The limit is in the word “party.” If someone is not formally named in the case, they cannot be served with interrogatories. That means bystander witnesses and unretained experts are off limits, and information from non-parties has to come through other tools like subpoenas or depositions.
Attorneys draft the questions and review the answers, but the party, not the lawyer, signs the responses under oath. You are personally vouching for every answer, which matters when the answers come back at trial.
The 25-Question Limit
Federal courts limit each party to 25 written interrogatories, counting all discrete subparts. You cannot dodge the cap by stuffing unrelated questions into lettered subparts under one number. Courts count each distinct question toward the total. A question that asks for several details about a single topic — the date, location, and attendees of one specific meeting — generally counts as one. A question that packs three unrelated topics into one number counts as three.
If 25 questions are not enough, the parties can agree in writing to allow more, or a party can ask the court for permission. Courts expect a real reason; blanket requests for a hundred extra questions rarely get granted. State courts set their own limits, which may be higher or lower.
What Interrogatories Can Ask About
The scope is broad. Interrogatories can cover any non-privileged matter relevant to a claim or defense. The information requested does not have to be admissible at trial, as long as the question is reasonably likely to lead to discoverable evidence.
Common subjects include:
- The factual basis for claims or defenses — what happened, when, where, and who was involved
- Names and contact information for witnesses with knowledge of relevant facts
- Identification of contracts, medical records, financial statements, and other documents that support or undermine a party’s position
- How the other side calculates the damages it claims
- Whether the responding party has insurance that might cover the claim
Courts can limit discovery that is cumulative, available more easily from another source, or whose burden outweighs the likely benefit given the stakes of the case.
How to Respond
Once you receive interrogatories, you have 30 days to serve written answers and any objections. The court or a written agreement between the parties can shorten or extend that deadline, but 30 days is the default under the federal rules.1Legal Information Institute. Federal Rules of Civil Procedure Rule 33 – Interrogatories to Parties Each question has to be answered separately and fully, and the party, not just the attorney, signs the responses under oath. The attorney signs any objections separately.
Answers must be honest, complete, and actually responsive to what was asked. “I don’t recall” is acceptable when it is genuinely true, but using it as a blanket response is a quick route to a motion to compel. The federal rules treat evasive or incomplete answers the same as no answer at all.2Legal Information Institute. Federal Rules of Civil Procedure Rule 37 – Failure to Make Disclosures or to Cooperate in Discovery; Sanctions
Pointing to Business Records
When the answer is in your business records, you can identify those records and give the other side a reasonable opportunity to examine them, instead of writing the answer out yourself. This only works when finding the answer in those records would take roughly the same effort for either party. You cannot bury the other side in unsorted paperwork and call it a response. The records you identify must be specific enough that the opposing party can locate the relevant information as easily as you could.
When You Can Object
You do not have to answer every question. If an interrogatory is improper, you can object, but you have to state the specific reason. “Objection” by itself is not enough. Common grounds include:
- Irrelevance, when the question has nothing to do with any claim or defense in the case
- Privilege, when the answer would reveal attorney-client communications, work product, or other legally protected material
- Overbreadth or undue burden, when answering would take disproportionate effort relative to the value of the information
- Vagueness, when the question is too unclear to answer meaningfully
If part of a question is proper and part is not, you still have to answer the proper part. Judges have little patience for boilerplate objections used to block legitimate discovery. If the asking party disagrees with your objection, they can file a motion to compel, and the court decides whether you have to answer.1Legal Information Institute. Federal Rules of Civil Procedure Rule 33 – Interrogatories to Parties
What Happens If You Don’t Respond
Ignoring interrogatories is one of the worst mistakes a party can make. The consequences escalate quickly.
The first move for the sending party is a motion to compel. Before filing one, they have to certify that they tried in good faith to get the answers without court involvement, typically by contacting the non-responsive party and asking them to comply.2Legal Information Institute. Federal Rules of Civil Procedure Rule 37 – Failure to Make Disclosures or to Cooperate in Discovery; Sanctions If that fails, the court takes over.
When a court grants a motion to compel, it will typically order the non-responsive party, or the attorney who advised the refusal, to pay the other side’s reasonable expenses for bringing the motion, including attorney’s fees. The court skips that award only if the non-response was substantially justified, the moving party did not try to resolve the dispute informally first, or other circumstances make the award unjust.2Legal Information Institute. Federal Rules of Civil Procedure Rule 37 – Failure to Make Disclosures or to Cooperate in Discovery; Sanctions
If a party keeps refusing after a court order, the available sanctions get severe. The court can treat disputed facts as established in the other side’s favor, prohibit the disobedient party from presenting certain evidence or defenses, strike their pleadings, dismiss the case, enter a default judgment, or hold the party in contempt.2Legal Information Institute. Federal Rules of Civil Procedure Rule 37 – Failure to Make Disclosures or to Cooperate in Discovery; Sanctions Refusing to answer interrogatories can cost you the whole case without a trial on the merits.
Penalties for Lying in Your Answers
Because interrogatory responses are signed under oath, lying in them carries the same legal risk as lying on the witness stand. Under federal law, anyone who willfully makes a false material statement under oath can be charged with perjury, punishable by up to five years in prison, a fine, or both.3Office of the Law Revision Counsel. 18 U.S. Code 1621 – Perjury Generally Perjury prosecutions over discovery responses are uncommon but do happen, and even without criminal charges, a party caught lying can expect sanctions, stricken pleadings, or adverse inferences that effectively decide the case.
If you do not know something, say so. If you are not sure, say that. What you cannot do is give an answer you know to be false.
How Your Answers Come Back at Trial
Interrogatory answers can be used at trial to the extent allowed by the rules of evidence.1Legal Information Institute. Federal Rules of Civil Procedure Rule 33 – Interrogatories to Parties The most common use is impeachment. If you testify one way on the stand but gave a different sworn answer in discovery, opposing counsel will read your written answer to the jury and ask you to explain the contradiction.
Your answers also work as admissions by a party opponent, meaning the other side can introduce them as evidence against you even if you never testify. Careless or overly broad answers stay dangerous long after discovery closes.
How They Compare to Other Discovery Tools
Interrogatories are one of several discovery methods, and experienced litigators pick the right tool for each job.
Depositions are live question-and-answer sessions, recorded by a court reporter, where the witness answers under oath in real time. The biggest practical difference is follow-up: in a deposition, an attorney can press immediately on an evasive or surprising answer. Interrogatories give the responding party time to craft careful answers with their lawyer, which makes them better for precise factual details and worse for catching someone off guard. Many attorneys use interrogatories first to map out the basic facts, then follow up with depositions to dig deeper.
Requests for production ask the other party to hand over specific documents, electronically stored information, or tangible things. Interrogatories ask for narrative answers. The two pair well: an interrogatory can identify which contracts exist, and a request for production can then demand copies of them.
Requests for admission ask the other side to admit or deny specific statements of fact. They do not seek new information; they narrow the issues for trial by establishing what is not in dispute. A fact admitted this way is treated as conclusively established, which is more powerful than an interrogatory answer that can still be explained away. The tradeoff is that requests for admission are blunt. They work for binary questions but cannot explore the open-ended territory interrogatories cover.