The mishap took place around 2 am when the driver lost control of the vehicle and it overturned and plunged into a ditch killing the four pilgrims on the spot and injured 17 others, they said.
The bodies have been sent for post-mortem and the injured were admitted to various hospital's for medical treatment.
The pilgrims, natives of Jharkhand's Giridih district, were going to a religious place at Sultanganj in Bihar's Bhagalpur district, the sources added.
