Missouri Small Claims Demand Letter

Before you fill out the petition and pay the filing fee, send a demand letter. It costs almost nothing, it resolves a surprising number of disputes without court, and for some claims it documents a demand date relevant to prejudgment interest.

Why Send One

Missouri law does not require a demand letter before filing most small claims cases. But there are practical and legal reasons to send one anyway.

Prejudgment interest. Under RSMo § 408.020, interest is 9% per year when no other rate is agreed. For a written contract, interest can run once the amount is due and payable; for an account, a demand of payment is required. A written demand for a specific, ascertainable amount can document that demand date. Whether interest is available depends on the legal basis for the claim.

Settlement. People who ignore your phone calls and texts often pay within days of receiving a formal letter with "small claims court" in it. The letter signals that ignoring you now has a cost.

Evidence. The letter and the certified mail receipt become part of your evidence file at the hearing. They show the judge you gave the other side a fair chance to resolve the dispute before filing.

What to Include

Keep it factual. A demand letter is not a legal brief — it is a clear statement of what happened, what you are owed, and what happens next if they do not pay.

1. The recipient's full legal name and mailing address. If you are writing to a business, use the legal entity name from the Missouri Secretary of State database, not the storefront name
2. A plain description of the dispute — dates, amounts, what was promised, what actually happened
3. The exact dollar amount you are demanding
4. A payment deadline — 10 to 14 business days is standard
5. A statement that you will file in small claims court if the deadline passes without payment
6. Copies of supporting documents — the invoice, the contract, the repair estimate, photos. Send copies, not originals

Do not threaten anything beyond filing a court case. Do not call the other person names. Do not speculate about what the judge will do. Judges read these letters at hearings, and a measured, factual tone helps your credibility.

Security Deposit Cases: The Built-In Demand

For residential security deposits, Missouri already has a statutory deadline built into the law. Under RSMo § 535.300, the landlord has 30 days after the date the tenancy terminates to either return the deposit or send an itemized list of deductions and any remaining balance. If they do neither, you can file for twice the amount wrongfully withheld.

A demand letter in a security deposit case recites the statute, states the move-out date, notes that the 30 days have passed, and demands the full deposit (or the amount wrongfully withheld). It also puts the landlord on notice that you will seek double damages under § 535.300.

How to Send It

Certified mail, return receipt requested. This gives you a record of the attempted delivery and, if signed, a signed proof of delivery (the green card). Keep that record in your evidence binder. Rule 54.16 applies to court process, not a private demand letter: if court process is returned as refused, the clerk may complete service by ordinary first-class mail with a certificate of mailing, as the rule allows.

Keep a photocopy of the letter itself, plus the certified mail receipt and (when it comes back) the signed green card. Store them together — they form the first tab of your evidence file.

What If They Ignore It

If the deadline passes with no response and no payment, you file the petition. The demand letter documents your request and may establish the demand date for a qualifying interest claim under § 408.020.

Our Missouri Small Claims Filing Guide includes a demand letter worksheet with fillable fields for every required element, plus the certified mail tracking log.

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