They were freed near Batia forest in the district, Additional Director General of Police (Law and Order) S.K. Bhardawaj told IANS over phone.
He said the release was a result of combing operations by the police.
"The Maoists were compelled to release them," he said.
They were abducted early Tuesday at Balthara village in Jamui, about 200 km from Patna, when over three dozen armed guerrillas stormed the office of a private construction company.
Police suspect the workers were kidnapped as the company refused to pay "protection money" to the rebels.
Jamui is considered to be a Maoist stronghold.