 After Denis Sassou Nguesso returned to power in October 1997, Mboulou served as Director-General of the Control of Markets and State Contracts from 1998 to 2002.In the May 2002 parliamentary election, he was again elected to the National Assembly as the candidate of the Congolese Labour Party (PCT) in Mpouya constituency; he won the seat in the first round with 80.15% of the vote.After the election, he was Head of the Cabinet of Aimé Emmanuel Yoka, the Director of the Presidential Cabinet, from 2002 to 2007.