Missouri Emissions Test

The Gateway Vehicle Inspection Program covers 4 Missouri areas, where gas, hybrid, and diesel cars are tested. For 2026, the covered model-year range is 1996 to 2024. Your car needs it every 2 years (odd model years match odd years, even match even) and again at sale.

What cars need testing?

In 2026, the green band marks which model years Missouri tests. If a new car had under 6,000 miles when first sold, it is exempt for its model year plus the following one. Gas cars from 1995 and older, plus diesels from 1996 and older, do not need testing.

For your own car, use its model year and fuel to check it.

Missouri emissions test at a glance

Program	The Gateway Vehicle Inspection Program
Where	St. Louis City, St. Charles County, Jefferson County, St. Louis County are the 4 areas.
Fuels tested	Gas, hybrid, diesel
Model years tested in 2026	1996 to 2024 (diesels from 1997)
How often	Required every 2 years (odd model years match odd years, even match even) and at sale
The test	An OBD plug-in test
Fee	Up to $24
Retest	The same station gives one free re-inspection within 20 working days
New cars	A new car skips the test for its model year and the year after if it had under 6,000 miles when first sold
Older cars	No test for gas cars from 1995 and older or diesels from 1996 and older
Waiver	Qualified repairs of at least $450 at a licensed shop can lead to a cost-based waiver, with labor counted only from a Missouri Recognized Repair Technician

How the test works, and what if the car fails?

The inspector connects a reader to the port below the dashboard during an OBD plug-in test, then reads what the car computer stored. Your check engine light must stay off, and the self-checks (readiness monitors) must be complete.

A fail means the report lists what did not pass. Fix that first, then return to the same station within 20 working days for one free re-inspection.

Missouri allows a cost-based waiver when a car still fails after repairs. Spend at least $450 on qualified work at a licensed shop, and have a Missouri Recognized Repair Technician do any labor that counts.

What failed? · Fix it, sell, or get a waiver?

Pages that back up these Missouri rules