Montana's DUI laws used to be at MCA § 61-8-401 and the sections after it. They are now at MCA §§ 61-8-1001 to 61-8-1033. The 2021 Legislature repealed the old sections and enacted a new part of the code, and the Department of Justice's prosecutor manual states the change took effect January 1, 2022. The table below matches each old section to its current home. This page is part of our Montana DUI Guide.
What Happened in 2021
Before the rewrite, the DUI offenses sat in Title 61, chapter 8, part 4, and the penalties sat separately in part 7 of the same chapter. Chapter 498, Laws of 2021, repealed both sets and created part 10, "Driving Under Influence of Alcohol or Drugs," which holds the offenses, the penalties, implied consent, and the evidence rules in one place. In the current code, each old section still has an entry, and it reads "Repealed. Sec. 44, Ch. 498, L. 2021."
Old Section to New Section
We built this table by comparing the section titles and text of the 2019 Montana Code Annotated with the 2025 edition. Where an old section was split, both destinations are listed.
| Old MCA section | Subject | Current MCA section |
|---|---|---|
| § 61-8-401 | Driving under the influence of alcohol or drugs; definitions; inferences | § 61-8-1002(1)(a) and (2); definition now in 61-1-101 |
| § 61-8-402 | Implied consent; refusal; administrative license suspension | § 61-8-1016 and 61-8-1032 |
| § 61-8-403 | Right of appeal to court (refusal suspension) | § 61-8-1017 |
| § 61-8-404 | Evidence admissible; conditions of admissibility | § 61-8-1018 |
| § 61-8-405 | Administration of tests; independent blood test | § 61-8-1019 |
| § 61-8-406 | Alcohol concentration of 0.08, or 0.04 in a commercial vehicle | § 61-8-1002(1)(b) and (1)(c) |
| § 61-8-407 | Definition of alcohol concentration | § 61-8-1001(3) |
| § 61-8-408 | Multiple convictions prohibited | § 61-8-1002(6) |
| § 61-8-409 | Preliminary alcohol screening test | § 61-8-1016(1)(b) to (d) |
| § 61-8-410 | Under 21 with alcohol concentration of 0.02 | § 61-8-1002(1)(e); penalties in 61-8-1007(3) |
| § 61-8-411 | THC (delta-9-tetrahydrocannabinol) limit | § 61-8-1002(1)(d) |
| § 61-8-421 | Vehicle forfeiture procedure | § 61-8-1033 |
| § 61-8-440 | Ignition interlock: assisting or circumventing | § 61-8-1024 |
| § 61-8-441 | Department rules on ignition interlock devices | § 61-8-1025 |
| § 61-8-442 | Ignition interlock or testing program on a first offense; 24/7 program and forfeiture on later offenses | § 61-8-1010 |
| § 61-8-460 | Open alcoholic beverage container in a motor vehicle | § 61-8-1026 |
| § 61-8-461 | Open container definitions | § 61-8-1001 |
| § 61-8-465 | Aggravated DUI | § 61-8-1001(1) (definition); penalties in 61-8-1007(4) |
| § 61-8-714 | Penalty for DUI, first through third offense | § 61-8-1007(1) |
| § 61-8-722 | Penalty for excessive alcohol concentration or THC, first through third offense | § 61-8-1007(2) |
| § 61-8-731 | Penalty for fourth or subsequent offense | § 61-8-1008 |
| § 61-8-732 | Assessment, education, and treatment | § 61-8-1009 |
| § 61-8-733 | Ignition interlock, 24/7 program, vehicle forfeiture on a second or later conviction | § 61-8-1010 |
| § 61-8-734 | Conviction defined; place of imprisonment; no deferred sentence | § 61-8-1011 |
| § 61-8-741 | DUI court: suspension of jail sentence; definition | § 61-8-1031; definition in 61-8-1001(8) |
One current section has no predecessor in the old DUI part: § 61-8-1027, on marijuana in a motor vehicle, was enacted by a different 2021 law.
It Was Not Only a Renumbering
Much of the wording carried over. Some of the structure did not, and two differences are worth knowing.
- One offense section. The old code had separate sections for impairment (§ 61-8-401), the 0.08 and 0.04 limits (§ 61-8-406), under-21 drivers (§ 61-8-410), and THC (§ 61-8-411). They are now subsections of a single statute, § 61-8-1002(1). See per se vs. impairment DUI.
- Aggravated DUI became a definition. Old § 61-8-465 began "A person commits the offense of aggravated driving under the influence." Today aggravated DUI is a defined term in § 61-8-1001(1), and a DUI that meets the definition is punished under § 61-8-1007(4). The list of aggravating facts also changed. The old section included having a prior conviction or pending charge within 10 years. The current definition does not list that. See aggravated DUI.
The Legislature has also amended part 10 since it took effect, in 2023 and in 2025. See what changed in 2025.
Do Old Convictions Still Count?
Yes. The current definition of a prior conviction covers a conviction for DUI under § 61-8-1002 "or a similar offense under previous laws of this state or the laws of another state" (MCA § 61-8-1011(1)(a)(iii)). A judgment that says § 61-8-401 or § 61-8-406 is counted the same way as one under the new numbers.
Whether it raises the offense number depends on timing. A prior counts toward a second offense if fewer than 10 years passed between that conviction and the new offense, and every prior counts once the new charge would be a third or later (MCA § 61-8-1011(1)(b)). See how long a DUI stays on your record and second and third DUI.
Do Old Court Decisions Still Apply?
Montana Supreme Court opinions from before 2022 cite the old numbers. They are still the main source for how DUI law is interpreted. The Department of Justice's 2023 DUI reference manual for prosecutors puts it this way: because the new statutes are substantively similar, "it is generally assumed the pre-2022 caselaw will persist until or unless overruled." That is an assumption, not a certainty. When an old case turns on wording the Legislature changed, the argument is open again.
When you read an older case, translate the citation with the table above. A reference to § 61-8-404 is about what is now § 61-8-1018, and a reference to § 61-8-402 is about what is now § 61-8-1016.
Stale Numbers Elsewhere in the Code
The cleanup was not perfect. At least one other statute still points to the repealed part: the bail statute that lets an officer accept a driver's license in place of bail for certain traffic offenses makes an exception for "chapter 8, part 4" (MCA § 46-9-302(2)(b)), which is where DUI used to be. How a court treats a stale reference like that is a question for your lawyer, not something to assume.
How to Check a Citation Yourself
- Look at the section number. Anything from § 61-8-401 to § 61-8-465, or § 61-8-714, 722, or 731 to 741, is the old scheme.
- Look up the section in the current Montana Code Annotated on the Legislature's website. A repealed section says so.
- Check the date of whatever you are reading. A DUI article written before 2022 uses the old numbers, and one written before October 2025 misses the most recent changes.
For the terms that appear on a current citation, see DUI vs. DWI: terms and legal limits and reading your DUI citation.
This page compares the 2019 and 2025 editions of the Montana Code Annotated. It is a research aid, not legal advice about your specific case.