Police Scotland are appealing for witnesses to the accident that happened at around 8pm on Sunday evening on the B9016 Keith to Buckie road at the Croft of Ryeriggs near Aultmore.
The 29-year-old man was riding a Suzuki GSXR motorcycle when it collided with a purple Mazda 3 car.
Investigators remained on the scene for around seven hours during which time the road remained closed.
Senior investigating officer Sergeant Jon Barron said: “Detailed enquiries are under way in order to establish the full circumstances of this serious collision.
“I would like to take this opportunity to urge any potential witnesses to come forward and speak to us. In particular, the enquiry team are interested in speaking to anyone who witnessed the actual collision and anyone who saw either of the vehicles prior to the incident or who may have been driving in the immediate area around the time.”
Witnesses are requested to contact Police Scotland on 101.