The accident took place near Ekauna village when the bus, on its way to Ara from Sahar, collided head on with the jeep going to Belaur from Ara, Station House Officer of Udwantnagar police station Mithlesh Kumar said.
Four persons were killed and 13 were seriously injured in the accident, he said.
They were referred to the Patna Medical College and Hospital while the seven with less injury were admitted at the Sadar hospital in Ara.