The mishap occured last night under Narhi police station area and all the six passengers of the jeep, on their way to Buxar from Ballia, were injured.
Two of them, Jaishankar Pandey and Shankar Bind, both 35 years old, died during treatment at the district hospital during treatment, they said.
Two others, who sustained serious injuries, were referred to Varanasi hospital.
The bodies have been sent for post-mortem, police added.