A bus overturned at Inderbani village of Dumka district, killing two people on the spot and injuring 28 others, they said.
The injured were admitted to Dumka hospital with the condition of five of them stated to be serious.
The passengers were returning to Murshidabad in West Bengal after attending a function.
In another accident, one person died when his car collided with another vehicle on Grand Trunk road in Bagodar police station in Giridih district, sources said.
In the third accident, 24 persons were injured when their bus collided with a truck near Jalebiya ghati under Pirtand police station in Giridih tonight, police said.
The condition of three of them were serious, the sources added.
In the yet another mishap, eleven persons got injured when a vehicle overturned in Latko village in Giridih district.
The condition of two of the injured was stated to be critical, sources said.