Police are appealing for witnesses after the incident on the B9126 around 2.40 pm on Sunday.
The 35-year-old man was cycling along the road in Kirkton of Skene when he came off his bike.
Members of the public stopped to assist him and called the paramedics who attended, but he died at the scene.
Inspector Lorraine Mackie, North East Road Policing Unit, said: "Our thoughts are with the family and friends of the man who died.
"Enquiries are ongoing to establish why the man came off his bike and so we are keen to speak to anyone who may have been on that road between 2pm and 3pm yesterday and who may have information or dash cam footage.
"In particular, we are keen to trace the driver of a dark coloured 4 x 4 vehicle which was travelling north at the time.”