Liam Thornton, 26, was injured in the crash on the A956 Charleston Flyover in Aberdeen at around 6pm yesterday.
A four-year-old boy and a woman were also hurt in the collision between a silver Vauxhall Corsa and a blue Ford Focus.
Mr Thornton, from Aberdeen, had been a passenger in the Corsa. He was taken to Aberdeen Royal Infirmary for treatment but later died.
Police said the boy and woman were also taken to Aberdeen Royal Infirmary, and the woman is in a serious condition. The child is not seriously injured.
Sergeant Rob Warnock, of the Aberdeenshire and Moray Road Policing Unit, said: "This is a tragic incident that has sadly resulted in a 26-year-old man losing his life.
"Investigations into the cause of the collision are at an early stage and I would urge anyone who witnessed the collision and hasn't spoken to police to do so.
"Additionally, anyone who may have seen the vehicles prior to the incident is asked to contact us."