A motorcyclist was taken to hospital following a collision on the Lisnevenagh Road in Ballymena.
Police say a motorbike and van collided at around 12.20pm on Saturday afternoon, on the north-bound carriageway, near the junction with the Woodgreen Road.
PSNI officers, the Northern Ireland Ambulance Service and Air Ambulance attended.
Police are appealing for witnesses.
The motorcyclist was taken to hospital following the collision where he remains in a serious condition. The van driver was spoken to at the scene and was not injured.
Officers would appeal to anyone who witnessed the collision, or who has dashcam footage which could assist with their enquiries to contact police in Ballymena on 101, quoting reference 656 09/05/26.