Police were contacted by the ambulance service at 10.48am who were attending a serious road traffic collision on the A659 Harewood Road at East Keswick.
The collision involved a motorcycle and a car.
The rider of the motorcycle, a 19-year-old man, received serious injuries and was taken to Leeds General Infirmary for emergency treatment.
A road closure is currently in place on the A659 between Collingham and Harewood for collision investigation work.
The scene is likely to remain in place for some time and drivers are advised to avoid the area.
Anyone who witnessed the incident is asked to contact officers via 101 quoting log 535 of April 23.