The accident occurred when the car in which they were travelling hit a roadside tree near Shantipur under Dergaon police station when they were travelling to ISBT-Jorhat.
The deceased was identified as Abhijit Pujari (45) and the injured were his wife Rupali Pujari, brother-in-law Debojit Borthakur and the driver, Rontumoni Borah, the police said.
All three injured were admitted to Jorhat Medical College Hospital.