The collision between a black Kawasaki motorbike and a black Mitsubishi Outlander happened at about 2.30pm on Friday on the A85, east of the village of Connel.
Emergency services attended and a 62-year-old man was taken to Lorne and Islands District and General Hospital where he was pronounced dead.
Police said they want to speak to the driver of a white Transit van who may have witnessed the accident.
Inspector Archie McGuire, of Argyll and West Dunbartonshire Road Policing Unit, said: “We are appealing to anyone who may have any information surrounding the crash, specifically a white Transit van who was on the road at the time of the incident.
“I would also appeal to anyone who has any dashcam footage of the area to come forward and speak to police.”
Anyone with any information can contact police on 101.