If your landlord is sitting on your deposit, Missouri law gives you a hard deadline and a real penalty — and a properly cited demand letter is how you invoke both. Here is exactly what Mo. Rev. Stat. § 535.300 requires.

Missouri's deposit rules at a glance

Return deadlineReturn the full deposit or itemized written deductions within 30 days of termination (§ 535.300.3)
The penaltyWrongful withholding: the tenant shall recover as damages twice the amount wrongfully withheld (§ 535.300.6); deposit capped at 2 months' rent

Thirty days, strictly enforced

Under RSMo 535.300, your landlord has 30 days from the end of the tenancy to return the full deposit or deliver an itemized list of damages with the balance. Missouri courts treat the statute as a consumer-protection law and enforce it strictly — an itemization mailed on day 34 is legally the same as no itemization, and courts have voided otherwise-legitimate deductions for exactly that mistake.

Mandatory double damages

Section 535.300.6 reads that a tenant 'shall recover as damages twice the amount wrongfully withheld.' The word shall removes judicial discretion: prove the wrongful withholding and the doubling follows automatically. A $1,300 deposit kept past the deadline is a $2,600 liability before court costs.

Your inspection right

Missouri requires the landlord to give you reasonable written notice of the date and time of the move-out inspection, and you have the statutory right to be present. Deductions assessed at an inspection you were never noticed for start the dispute compromised — note it in your letter.

The guardrails

Deposits are capped at two months' rent and must be held in a federally insured institution. Lease clauses that conflict with § 535.300 are unenforceable. Small claims courts (limit $5,000) handle these cases routinely; a demand letter that cites the statute, states the dates, and computes the doubled figure usually makes the filing unnecessary.

What a strong Missouri demand letter looks like

It states the deposit amount, the move-out date, the statutory deadline that passed, and the penalty exposure in dollars — citing Mo. Rev. Stat. § 535.300 by name. Here's how the opening of a strong one reads:

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Missouri Security Deposit Demand — Preview
[Your Name] [Your New Address] [City, MO ZIP] [Date] [Landlord Name] [Landlord Address] RE: Demand for Return of Security Deposit — Mo. Rev. Stat. § 535.300 — [Former Property Address] Dear [Landlord Name], I am writing to formally demand the return of my security deposit in the amount of $[AMOUNT] for the above property, which I vacated on [MOVE-OUT DATE]. Under Mo. Rev. Stat. § 535.300.3, you were required to return my deposit or provide an itemized list of damages within thirty (30) days. As of today, [NUMBER] days have passed. Be advised that under § 535.300.6, the wrongful withholding of all or any portion of a security deposit entitles the tenant to recover as damages twice the amount wrongfully withheld — a mandatory award... Accordingly, demand is hereby made for payment of $[AMOUNT], together with all statutory penalties described above, within ten (10) days of the date of this letter — no later than [RESPONSE DEADLINE]. If payment is not received by that date, I will file suit in small claims court without further notice, where I will seek the full statutory penalty, court costs, and every other remedy available under law. I would prefer to resolve this without litigation — but I am fully prepared to proceed. Govern yourself accordingly, [Your Name]

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This guide is general information about Missouri law, not legal advice. Statutes are paraphrased; verify current law for your situation. For significant or contested claims, consult a licensed Missouri attorney.

Already hearing from a collection agency?

Landlords hand move-out balances to a small set of specialist collectors. If the letter is from National Credit Systems, Hunter Warfield, IQ Data International, or Source RM, we have a company-specific response guide for each — and the demand letter on this page still applies, because a landlord who missed the statutory deadline may owe you money regardless of who is calling. Any other collector: see the collection agency index and your state’s rules in the debt statute of limitations guide.