One woman was airlifted to hospital with serious injuries after the crash on the A470 between Betws-y-Coed and Llanrwst on Sunday at 13:30 BST.
A man and woman were also taken to hospital after the collision involving a white BMW car and motorbike. The male motorcyclist died at the scene.
North Wales Police are appealing for witnesses to the crash.
A motorcyclist has died and three other people have been hurt in a collision with a car in Conwy county.