Filing a lawsuit is not the end of the beginning — it is the beginning of the middle. After the petition is filed and the defendant answers, the case enters a phase called discovery. This is where both sides investigate each other's claims and defenses by exchanging information, documents, and testimony under court supervision.

Discovery is often the longest phase of litigation. It can take six months to over a year. It is rarely dramatic. But the information gathered during discovery determines whether your case settles for fair value, goes to trial on solid footing, or collapses under the weight of facts you did not anticipate.

The Purpose of Discovery

The American legal system operates on the principle that trials should not be contests of surprise. Both sides are entitled to know the evidence the other side plans to present. Discovery serves this principle by requiring the exchange of relevant information.

Discovery accomplishes several objectives:

Fact gathering. You learn what the other side knows, what documents they possess, and what their witnesses will say. This information shapes your trial strategy.

Narrowing the issues. As both sides exchange information, undisputed facts emerge. The case narrows to the genuinely contested issues, making settlement negotiations more focused and trial more efficient.

Preserving testimony. Depositions preserve witness testimony under oath. If a witness becomes unavailable at trial — due to illness, relocation, or death — their deposition testimony can be used instead.

Evaluating case strength. Discovery reveals the strengths and weaknesses of both sides. This evaluation drives settlement: cases settle when both sides have enough information to assess the likely trial outcome.

Types of Discovery in Missouri

Interrogatories

Interrogatories are written questions that one party sends to the other. The receiving party must answer them under oath within 30 days (45 days for a defendant, measured from the earlier of appearance or service of process). Missouri Supreme Court Rule 57.01 governs interrogatories. Since the 2021 amendments, parties are limited to 25 interrogatories — including discrete subparts — unless the court grants leave or the parties stipulate otherwise.

In a personal injury case, typical interrogatories ask the plaintiff to:

List all healthcare providers who treated the injuries
Describe the accident in detail
Identify all witnesses
Disclose prior injuries or medical conditions
Itemize economic damages

Interrogatories are useful for gathering basic facts and identifying the universe of relevant documents and witnesses. They are less useful for probing nuance — written answers are carefully crafted with attorney input and rarely reveal the kind of detail that emerges in deposition testimony.

Requests for Production of Documents

Document requests require the other side to produce relevant documents under Missouri Supreme Court Rule 58.01. In personal injury cases, this includes medical records, medical bills, employment records, tax returns, photographs, correspondence with insurance companies, and cell phone records.

The scope of document discovery is broad: any document that is relevant to a claim or defense — or proportional to the needs of the case — is discoverable. Privacy concerns can limit discovery in some areas, but Missouri courts generally favor disclosure. Since the 2021 amendments aligned Missouri practice more closely with the federal proportionality standard, courts weigh the importance of the issues at stake, the amount in controversy, the parties' relative access to relevant information, and the burden or expense of the proposed discovery.

Electronic discovery — emails, text messages, social media content, and metadata — has expanded the scope of document production dramatically. Preserving electronic evidence is now a critical obligation that begins as soon as litigation is reasonably anticipated. Social media posts, direct messages, cloud-stored files, and even ephemeral messaging app content may all be discoverable if relevant to a claim or defense.

AI-generated content. Courts are increasingly addressing whether AI-generated outputs — including prompts, model responses, and activity logs — fall within traditional discovery obligations. Recent federal rulings have held that GenAI data is discoverable when tied to a claim or defense, and parties who use AI tools in connection with the facts of their case should anticipate preservation obligations extending to those interactions.

Depositions

Depositions are the most revealing discovery tool. A witness answers questions under oath while a court reporter records the testimony. Missouri Supreme Court Rules 57.03 and 57.04 govern depositions. Since the 2021 amendments, depositions are limited to ten per party and one day of seven hours per deponent, unless the court orders otherwise or the parties agree to different terms. Unlike interrogatories, deposition answers are spontaneous — the witness cannot consult with their attorney before responding to each question.

Both parties, expert witnesses, treating physicians, and non-party witnesses can be deposed. Deposition testimony is admissible at trial for impeachment and, in some circumstances, as substantive evidence. For a detailed look at what happens during this process, see What to Expect During a Deposition in Missouri.

Requests for Admission

Under Missouri Supreme Court Rule 59.01, requests for admission ask the other side to admit or deny specific facts. Parties are limited to 25 requests without leave of court, consistent with the 2021 discovery amendments. If a fact is admitted, it is established for trial and does not need to be proven. If denied, the requesting party can seek costs if they later prove the denied fact at trial.

Strategic use of requests for admission narrows the issues for trial. Common admissions in personal injury cases include:

The defendant was the driver of the other vehicle
The accident occurred at a specific location on a specific date
The plaintiff incurred specific medical expenses

Physical and Mental Examinations

Under Missouri Supreme Court Rule 60.01, the defendant can request a court order requiring the plaintiff to submit to an independent medical examination. The examining physician — chosen by the defense — evaluates the plaintiff's injuries and provides a report.

These examinations are a frequent source of dispute. The defense characterizes them as "independent." Plaintiffs often view them as adversarial, since the examining physician is selected and paid by the defense. Regardless, the examination and resulting report are important components of the evidence landscape.

Discovery Disputes

Not everything requested in discovery is produced without objection. Common disputes include:

Relevance objections. One side argues that the requested information is not relevant to any claim or defense. The requesting party argues it is — or that it could lead to relevant evidence.

Privilege objections. Communications between attorney and client are protected by attorney-client privilege. Work product — documents prepared in anticipation of litigation — receives qualified protection. These privileges have boundaries, and disputes about their scope are common.

Overbreadth. A request for "all documents relating to any medical treatment you have ever received" may be objected to as overbroad. Courts typically narrow such requests to a reasonable scope — treatment related to the injured body parts within a relevant time period.

Privacy. Requests for social media passwords, personal financial records, or medical records unrelated to the claimed injuries raise privacy concerns. Courts balance the need for discovery against the intrusiveness of the request.

When parties cannot resolve discovery disputes themselves, either side can file a motion to compel. Under Rule 61.01, the judge decides whether the disputed discovery must be produced, sometimes after an in-camera review of the contested materials. Understanding how evidence rules affect your case is critical during this phase, because the admissibility of the evidence you fight to obtain — or protect — often determines the outcome at trial.

Discovery Obligations and Consequences

Both parties have an ongoing obligation to supplement their discovery responses. If new information becomes available — a new witness, additional medical treatment, a change in employment status — the opposing side must be notified.

Failure to comply with discovery obligations carries consequences:

Sanctions. Courts can impose monetary sanctions for discovery abuse — refusing to produce documents, providing evasive answers, or failing to attend depositions.

Evidence exclusion. If a party fails to disclose a witness or document during discovery, the court may prohibit them from using that evidence at trial. This can be case-determinative.

Adverse inference. If a party destroys evidence that should have been preserved, the court may instruct the jury to infer that the destroyed evidence was unfavorable to that party. Note that Missouri's revised discovery rules do not contain a specific preservation provision for electronically stored information comparable to Federal Rule 37(e). However, Rule 61.01(d) authorizes sanctions for failure to produce ESI, and Missouri courts apply traditional spoliation principles — including adverse inference instructions — when electronic evidence is destroyed in bad faith.

The Discovery Timeline

In Missouri state court, the discovery period is governed by the case management order issued by the judge. A typical timeline:

Months 1-3: Initial disclosures, interrogatories, document requests
Months 3-6: Depositions of parties
Months 6-9: Expert witness disclosures, expert depositions
Months 9-12: Discovery closes, motions filed
Month 12+: Trial preparation, settlement conferences

Federal court timelines are similar but often more compressed, with stricter deadlines enforced by the scheduling order.

Understanding how attorneys evaluate your case value helps explain why discovery drives settlement: the information gathered during this phase directly determines the value both sides assign to the case.

2026 Rule Update. On February 24, 2026, the Supreme Court of Missouri issued an order amending Rule 56.01 (General Provision Governing Discovery), with an effective date of January 1, 2027. Practitioners should review the amended text — available through the Missouri Bar's QuickRead summary — to prepare for any changes to discovery scope or procedure.

FAQ

Can the other side see my medical records?

In a personal injury case, your medical records related to the injuries you claim are discoverable. The defense is entitled to records from your treating physicians, hospitals, and specialists. Records for unrelated medical conditions may be protected, but the defendant can argue that prior conditions affecting the same body parts are relevant.

Do I have to answer every interrogatory?

You must answer interrogatories that seek relevant information, but your attorney can object to questions that are overbroad, unduly burdensome, or seek privileged information. Objections must be stated with specificity, and the objecting party typically must still answer to the extent the question is not objectionable.

What happens if I lose or delete relevant documents?

Destroying relevant evidence after litigation has begun — or after you reasonably should have anticipated litigation — can result in severe sanctions, including adverse inference instructions, monetary penalties, or even dismissal of your case. Preserve all potentially relevant documents, electronic files, and physical evidence.

Can discovery be used in settlement negotiations?

Absolutely. Discovery is the primary driver of settlement. Once both sides have exchanged evidence, deposed key witnesses, and obtained expert opinions, they have enough information to evaluate the case realistically. Most cases settle after discovery is substantially complete.

How much does discovery cost?

Discovery is typically the most expensive phase of litigation. Costs include attorney time for drafting and responding to written discovery, deposition transcript fees, expert witness fees, and document production expenses. In a moderately complex personal injury case, discovery costs can range from several thousand to tens of thousands of dollars.

Discovery is where litigation cases are built or broken. Whether you are navigating a personal injury claim, a business dispute, or a breach of contract, the discovery phase demands strategic planning and thorough execution.

For case referrals or co-counsel inquiries, contact Joseph Ott at joe@ott.law or (314) 710-2740.

This article is for informational purposes only and does not constitute legal advice. Every case is different. Contact OTT Law at (314) 710-2740 for a free consultation specific to your situation.

What Is Discovery in a Missouri Lawsuit?