Hurt at Work in Missouri? The 30-Day Notice Rule and the 2-Year Deadline to File a Workers' Comp Claim

How long do you have to report a work injury in Missouri? As of 2026, Missouri law generally requires you to give your employer written notice of the injury within 30 days (RSMo 287.420). Separately, a Claim for Compensation generally must be filed with the Missouri Division of Workers' Compensation within two years after the injury or the last payment of benefits. That becomes three years if your employer did not file its required report of injury (RSMo 287.430).

Those are two different steps with two different clocks. This post explains each one, what happens if you missed one, and what to gather now. For a broader overview, see our workers' compensation claims page.

How long do you have to report a work injury in Missouri? Two deadlines, not one

Many people assume that telling a boss about an injury "starts the claim." It does not.

• Notice to your employer tells the company you were hurt. The deadline is generally 30 days.
• A Claim for Compensation is a formal filing with the state Division of Workers' Compensation. The Division says filing it begins a contested case in which an administrative law judge has authority to decide the issues. The deadline is generally two years, sometimes three.

You can meet the first deadline and still miss the second. These rules are set by statute and can be changed by the legislature, so the deadlines described here are accurate as of 2026.

The 30-day written notice to your employer

What the notice must include

Under RSMo 287.420, the written notice must state:

• the time of the injury,
• the place of the injury,
• the nature of the injury, and
• the name and address of the injured person.

For an accident, the notice is due no later than 30 days after the accident.

Why telling your supervisor out loud may not be enough

The statute calls for written notice. The Division's own guidance tells injured workers to notify the employer in writing, keep a copy, and keep a record of the date the notice was mailed. If you hand-deliver it, the Division recommends writing down the date, the time, and the full name and title of the person who received it. If your employer doesn't give you a form, the Division publishes one: Form WC-280.

Some older Missouri cases, decided before the current wording was adopted in 2005, treated other kinds of notice as enough. In one 1961 case, a doctor's phone call to the employer counted. Still, a written notice with a copy you keep avoids an argument about it later.

What if your notice was late?

Late notice does not automatically end a claim. For accidents, the statute says the claim may go forward if "the employer was not prejudiced by failure to receive the notice." The current statute does not use the phrase "actual notice." But if your employer already knew about the injury, that fact can matter when deciding whether the employer was harmed by the late written notice.

Who has to prove the employer wasn't prejudiced?

• Occupational disease and repetitive trauma: the statute expressly puts the burden on the employee.
• Accidents: the accident sentence doesn't say. A 1955 Missouri case placed the burden on the worker. That case predates the current wording, so an attorney should look at how it applies today.

Occupational disease and repetitive trauma

For conditions that develop over time, such as repetitive-motion injuries, the 30-day notice period runs from the diagnosis of the condition, not from a single event. The Division states the same rule on its occupational disease page.

The deadline to file a Claim for Compensation

Under RSMo 287.430, a claim must be filed with the Division within two years after the date of injury or death, or after the last payment made under the workers' compensation law on account of the injury. The Division's instructions for the claim form say "whichever is later," and say the Division must receive the form within that time.

The period becomes three years if the employer did not file the report of injury required by RSMo 287.380.

For occupational disease, RSMo 287.063 says the filing period does not begin until it "becomes reasonably discoverable and apparent" that an injury related to the work exposure has been sustained. Hearing loss from industrial noise follows its own timing rule.

The statute describes this limitation as one "of extinction," which signals that a claim filed too late can be lost entirely.

Paying your medical bills is not the same as filing a claim

RSMo 287.430 says the filing of any form, report, receipt or agreement "other than a claim for compensation" does not stop the clock. So an employer or insurer handling your bills does not mean a claim is on file with the Division.

Those payments can still matter. In Dungan v. Fuqua Homes (Mo. App. W.D., No. WD77068), the court measured the two years from the insurer's last payment for medical treatment. Payments from your own health insurance, Medicaid, or a spouse's plan generally do not count, because they aren't payments under the workers' compensation law.

Deadlines at a glance (as of 2026)

Where to file

The claim is made on Form WC-21, the Claim for Compensation. The Division instructs workers to complete it and mail it to the address on the form. The form is also available at any Division office. For the St. Louis area, the Division's "St. Louis office" is actually in Chesterfield: 1390 Timberlake Manor Pkwy, 5th Floor, Suite 580, Chesterfield, MO 63017 (314-340-6865). The Division's information line is 800-775-2667.

Your employer's own reporting duty

Under RSMo 287.380, the employer or its insurer must file a report of injury with the Division within 30 days after knowledge of the injury. The duty covers injuries for which the employer would owe medical aid or compensation. It does not cover immediate first aid that leads to no further treatment or lost time.

Employers must also report injuries to their insurance carrier or third-party administrator within five days of the injury or of the employee's report, whichever is later. The insurer or administrator then files the Division report. Knowingly failing to report is a misdemeanor under the statute, punishable by a fine of $50 to $500, county jail of one week to one year, or both.

This matters to you because a missing report can stretch the filing deadline to three years. To check whether a report was filed, the Division says to call 800-775-2667. One limit: under RSMo 287.430, a report filed three or more years after the injury or last payment does not revive an expired filing period.

What to do if you think you've missed a deadline

Don't assume your case is over. Whether the employer was prejudiced, when the condition was diagnosed, and the date of the last payment can all change the math. Start gathering:

• the date of the injury or diagnosis,
• who you told, when, and how (written or verbal),
• texts, emails, or copies of any written notice,
• medical visit records and who paid for each,
• any benefit checks or payment statements.

If you're worried about your job, note that RSMo 287.780 prohibits an employer from discharging or discriminating against an employee for exercising rights under the workers' compensation law, when that is the motivating factor.

If someone other than your employer caused the injury, such as another driver in a work-related crash, there may also be a separate claim. See our pages on personal injury and car crashes.

An attorney can review your timeline and documents and explain the options that apply to your facts.

Talk with a lawyer about your timeline

JMH Law Firm, LLC has offices at 223 N. Main Street, Suite 1, St. Charles, and 8821 Manchester Road, Brentwood. Call 314-827-6222 or contact us online to talk through your deadlines. You can also read more on our workers' compensation claims page.

This post is general information about Missouri law as of 2026, not legal advice for your situation.