The victims hailed from Digha in West Bengal and were going to Cuttack when the accident took place in the wee hours, a police official said.
While four persons died on the spot, the driver of the car sustained serious injuries and was rushed to SCB Medical College and Hospital in Cuttack for treatment, he said.
"On being informed, we reached the spot and pulled out the mangled car from below the truck with assistance of local people and fire brigade personnel," Inspector In-Charge of Dharmasala police station A Mohapatra said.
The bodies have been sent for postmortem Barachana community health centre (CHC). The kin of the deceased have been informed about the accident over phone, he said.