How to Find and Cite Missouri Law

Missouri's real estate appraiser rules used to sit in Title 4 of the Code of State Regulations. In 2006 the whole set moved to Title 20.

Not a word of those rules changed in the move. Their citations did. The definitions rule was filed as 4 CSR 245-2.010 and today it answers to 20 CSR 2245-2.010, for the plain reason that a title number in Missouri names a department, and the agency holding that rule ended up under a different one. Missouri's regulation book carries 2,663 sections in exactly that state, marked transferred, alongside 4,483 that were rescinded outright. Together that is 7,148 of 13,116 regulation sections that are no longer live rules, or 54% of the book, leaving 5,968 that are.

Who publishes what

Statutes are the Revised Statutes of Missouri. The Revisor of Statutes prepares and publishes them for the Committee on Legislative Research, a joint committee the 1945 Constitution established and the General Assembly put in charge of the statutes in 1949. RSMo 3.010 is the printing direction. What sits in print right now is the 2016 revision plus cumulative supplements, and the 2025 supplement replaced the 2024 one. Under RSMo 3.090 the language of a newly enacted section goes up on the Revisor's site on the day that section takes effect, and the Revisor's site says plainly that the statutes posted there are uncertified and unofficial.

Rules are a separate operation. The Secretary of State's Administrative Rules Division publishes the Code of State Regulations, the Missouri Register and any emergency rules. RSMo 536.031 establishes the CSR and requires it to be revised no less frequently than monthly, so it picks up every rule made, amended or rescinded since the last pass. The same section says Missouri courts take judicial notice of what the CSR contains, without proof. The Register comes out twice a month.

Citing a statute means citing a year

An RSMo cite carries a year, and that year is not the year the law passed. It names the printed revision or supplement you read the text in. RSMo 1.070 sets this up. RSMo stands for the Revised Statutes of Missouri, and RSMo Supp. followed by a year means the supplement the state published after that year's session finally adjourned.

You can watch the convention work inside the rules. The authority line under the appraiser definitions rule reads sections 339.503, 339.509, and 339.544, RSMo 2016, and a footnote below it gives the original authority as 339.503, RSMo 1990, amended in 1998, 2009, 2010 and 2012. Two different years doing two different jobs. One tells you where to read the current text. The other tells you when the rulemaking power was granted and how often it has been reworked since.

One more thing out of RSMo 1.070. When a Missouri statute points at a run of sections joined by the word to, the reference takes in both ends and everything between them. A cross reference to sections 339.500 to 339.549 is not a reference to two sections.

How many of the Missouri cites in your last memo carried a year?

Reading a CSR number

Read 20 CSR 2245-2.010 from the left. Title 20 is the Department of Commerce and Insurance. Division 2245 is the real estate appraisers commission inside it. Chapter 2 is that commission's general rules, and .010 is the rule itself.

So the first number is a department and the second is the agency under it. Which is why a reorganization renumbers rules by the thousand, and why a citation from an old file can be off by an entire title while the rule behind it has not moved a comma.

The history line is the audit trail

Under each rule sits a filing history, and it does more work than people give it credit for. That appraiser definitions rule lists an emergency rule filed in December 1990 that expired, a second emergency rule in 1991 that also expired, the original rule filed January 3, 1991 and effective April 29, 1991, then the move to 20 CSR 2245-2.010 effective August 28, 2006, then two amendments that took effect in 2013 and 2018.

Every one of those events is dated. If you are holding the old number, this is where the state tells you what the new one is, so start here rather than assuming the old cite went dead.

Rescissions are printed too. The table of contents for that chapter still lists 20 CSR 2245-2.040, Appraiser's Seal, with the words rescinded July 30, 2007 sitting right beside it.

When a Missouri rule actually binds anyone

The Register prints its own calendar, and it is worth reading before you promise a client a date. A rule filed by the January 2, 2026 deadline shows up in the February 2, 2026 Register, goes into the Code on February 28, 2026, and takes effect on March 30, 2026. Roughly two months from the filing cutoff to the day it binds anyone, with the Code publication date and the effective date a month apart.

Put that spacing in your own diary. A Missouri rule can be final, published and still not in force, and the Register is what tells you which of the three it is on any given day.

The shape of the Missouri material

These come from a US primary law corpus maintained by Vaquill AI, measured on 2026-09-18. Missouri holds 51,454 sections.

• Statutes: 29,354
• Regulations: 13,116, of which 5,968 are in force
• Attorney General opinions: 8,449
• Constitution: 429
• Agency guidance: 106

The attorney general figure stands out. 8,449 published opinions is a deep bench of interpretive material sitting beside a statute book of 29,354 sections, and it is a good early stop when a question turns on what some Missouri office has the power to do.

A short routine for an unfamiliar Missouri cite

1. If the cite is a statute, check whether it carries a year. Without one you cannot tell which revision or supplement the writer was reading.
2. If it is a rule, split it at the hyphen. Title and division before, chapter and rule after.
3. Pull the current rule and read its history line from the bottom up, looking for a move before you look for a rescission.
4. Check the authority line, and then check the footnote under the authority line. They carry different years on purpose.
5. Note which Code publication date your copy reflects, because the CSR gets revised monthly and yours may be a cycle behind.

And when you write a Missouri statute cite of your own, put the year on it. The next person to read it needs to know which book you had open.

Facts used

Priyansh Khodiyar

Co-Founder & CTO

Priyansh leads engineering and AI at Vaquill, from the matter workbench to drafting, document comparison, document matrix, and citation-verified research.