The victim died on the way to the hospital, raising the death toll to five, police said.
The incident took place near Goja bridge in Ramarchar area of Hatikumrul-Bonpara highway at around 2 am on Thursday, said Hatikumrul Highway Police Station chief Lutfar Rahman.
The dead have been identified as Mukul Hossain, 34, Monir Hossain, 35, Mokbul Hossain, 35, Abdul Halim, 40, and Haider Ali, 41.
The Laguna carrying farm labourers was on its way to Natore from Hatikumrul roundabout when it crashed with a truck coming from the opposite direction, OC Lutfar said.
The accident left four people dead on the spot and six others injured. Police later rescued the injured and sent them to different hospitals in Sirajganj and Rajshahi. Abdul Halim died succumbed to his injuries on the way.
The bodies and the vehicles have been taken into police custody, Lutfar said, but the driver and his assistant have fled.