What you need to register a new car in Missouri
When you buy a new car in Missouri, you register it through your county assessor's office, not through the state DMV. The assessor's office issues your registration certificate and license plates. You will need your purchase documents, proof of ownership from the dealer, a completed registration form, and proof of residency. Most new car purchases come with temporary tags from the dealer that give you time to complete registration — typically 30 days — so you do not have to rush to the assessor's office the same day you buy the vehicle.
The process itself is straightforward: you bring your documents to the assessor's office in the county where you live, pay the registration fee, and receive your permanent plates and registration certificate. Some counties allow you to mail in your registration, though in-person visits are more common for new vehicles because the assessor needs to verify the vehicle identification number (VIN) matches your paperwork.
Key Takeaways
- You register a new car through your county assessor's office, which is located in the county courthouse or a separate county building — not through a state office.
- Bring your bill of sale or purchase agreement, the dealer's temporary registration paperwork, proof of residency such as a utility bill or lease, and a completed MO 108 form (the registration process).
- Registration fees in Missouri vary by county and are based on the vehicle's value, so the cost depends on where you live and what you paid for the car.
- Dealer-issued temporary tags typically last 30 days, giving you time to complete registration without driving on expired plates.
- Some counties accept mail-in registration for new vehicles, but you should call your assessor's office first to confirm what documents they need and whether they will verify the VIN by mail.
Finding your county assessor's office
Your county assessor's office is the only place that handles vehicle registration in Missouri. The office is usually located in the county courthouse or in a separate county building downtown. To find the exact address and hours, search online for "[your county name] assessor's office" or call your county clerk's office — they can direct you to the right location and phone number.
Before you go, call the assessor's office and ask what documents they need for a new car registration. While the basic requirements are the same statewide, some counties have specific preferences about how documents should be organized or whether they accept mail-in registration. Asking ahead saves you a trip back home if you forget something.
Documents you will bring to the assessor's office
Gather these documents before you visit: your bill of sale or purchase agreement from the dealer, the temporary registration paperwork the dealer gave you, and proof of residency. Proof of residency can be a utility bill, lease agreement, mortgage statement, or bank statement with your current address — it must show your name and address and be dated within the last 60 days.
You will also need to complete the MO 108 form, which is the Missouri vehicle registration process. You can read this form from the Missouri Secretary of State website or pick up a copy at the assessor's office. Fill it out before you go, or ask the staff to help you complete it there — either way works. The form asks for your name, address, the vehicle's VIN, the purchase price, and the date you bought the car.
Bring your driver's license or state ID as well. If someone else is listed as the owner on the bill of sale, both owners should be present or you should bring a signed power of attorney from the absent owner.
Registration fees and how they are calculated
Missouri registration fees are based on the vehicle's value, and the amount varies by county. The state does not set a flat fee — each county assessor calculates the fee using a formula that considers the car's purchase price, age, and condition. A new car you just bought will have a higher registration fee than an older used car.
To find out the exact fee before you go, call your county assessor's office and tell them the vehicle's purchase price and model year. They can give you an estimate. Fees typically range from $100 to $300 for a new vehicle, but this varies widely depending on the car's value and your county's assessment rate. Bring a check or cash, though many assessor's offices now accept credit cards — call ahead to confirm what payment methods they take.
Temporary tags and how long you have to register
When you buy a new car from a dealer, the dealer issues temporary registration tags that are valid for 30 days. These tags allow you to drive the vehicle legally while you complete the permanent registration process. The temporary tags are usually printed on a sticker or paper plate that goes in your rear window.
You do not have to register the car on the day you buy it. You have the full 30 days to visit the assessor's office. However, do not wait until the last day — if the assessor's office is closed or busy, you could end up driving on expired tags. Plan to register within the first two weeks of purchase so you have a buffer.
If you need more time, some dealers can issue an extension of the temporary tags, though this is not may provide. Call the dealer and ask if they can extend your temporary registration if you need a few extra days.
What happens after you pay the registration fee
Once you pay the fee and the assessor's office processes your paperwork, you will receive your permanent license plates and a registration certificate. The registration certificate is a paper document that shows your name, the vehicle's VIN, the plate number, and the registration expiration date. Keep this certificate in your vehicle at all times — Missouri law requires you to have proof of registration with you when you drive.
Your license plates are yours to keep as long as you own the vehicle and renew your registration each year. When you renew, you will return to the same assessor's office or mail in your renewal paperwork — the office will send you renewal notices in the mail before your registration expires.
If the assessor's office mails your plates to you instead of handing them over in person, allow one to two weeks for delivery. In the meantime, your temporary tags remain valid, so you can keep driving legally.
If you are buying from a private seller instead of a dealer
If you are buying a new car from a private seller rather than a dealership, the process is slightly different because there are no temporary tags. You will need the seller's signature on the bill of sale, proof that they own the vehicle (usually the previous registration certificate), and a signed title transfer form. Take these documents directly to the assessor's office along with your proof of residency and the MO 108 registration form.
Do not drive the vehicle before you register it — without temporary tags from a dealer, you have no legal right to operate it on public roads. Complete the registration before you take the car home. This is why private sales often happen at the assessor's office or nearby, so both parties can handle the paperwork together.
Frequently Asked Questions
Can I register my new car by mail?
Some Missouri counties accept mail-in registration for new vehicles, but not all. Call your county assessor's office and ask whether they will process a new car registration through the mail and what documents they need. If they do accept mail-in registration, ask whether they will verify the VIN by mail or whether you need to bring the vehicle in person.
What if I move to a different county after I register?
If you move to a different Missouri county, you do not have to re-register your vehicle when ready. Your registration remains valid until the expiration date on your certificate. When it is time to renew, you will renew through your new county's assessor's office. Bring your current registration certificate and proof of your new address.
Do I need to register the car before I drive it off the dealer's lot?
No. The dealer's temporary tags are valid for 30 days, so you can drive the car home and register it at your convenience within that window. However, do not let the temporary tags expire — you must have permanent registration or valid temporary tags at all times.
What if the assessor's office loses my paperwork?
If you submitted your registration and the office cannot find it, ask to speak with a supervisor and bring copies of everything you submitted. The office should have a record of your payment if you paid by check or card. If there is a genuine error, the office will help you resubmit or issue a replacement registration certificate.
Can I get my license plates before I pay the full registration fee?
No. You must pay the full registration fee before the assessor's office issues your plates and registration certificate. There are no payment plans or partial registrations for new vehicles in Missouri.