You need a test if your vehicle is:
When do I get a test?
How long is the emissions test valid for registration?
60 days (or 120 for a car dealer).
Special Considerations

Low Mileage-Based (Emissions Inspection Exemption)
Available when a vehicle is:

Switched Engine Vehicles
Switched engine vehicles must have an emissions test even though the original manufacturer’s certified engine configuration has been removed and replaced with another engine. The vehicle’s readiness monitors must be set in order to test. There is no waiver for the cost of fixing and improperly installed or incorrect application engine. It must meet the original manufacturer’s criteria or owner is responsible for cost of returning it to the original manufacturer’s criteria.

Flex-Fuel, Dual Fuel and Hybrid Electric Vehicles
These vehicles are also subject to emissions testing:
Fuel Flex vehicles that burn:
Dual Fuel vehicles with tanks of:
Hybrid electric vehicles with gasoline or diesel engines.

Gray Market Vehicles
What if I don’t test?
Registration will be denied, you will not get new stickers and you won’t be able to legally drive your vehicle.
Vehicles that don’t need emissions testing
Even if you are exempt from emissions inspections you must have a safety inspection. Safety inspections are required every two years (regardless of calendar or model years) except for the vehicle’s first 10 model years or 150,000 miles.
Please call 314-416-2115 for any questions about emissions exemptions. See Waiver Applications and Exemption Requests for conditionally waived vehicles.

Find A License Office Near You

Additional Information
Government fleets and military personnel vehicles in the St. Louis area must have an emissions test.