The people of South Bougainville now have a new MP in the National Parliament, after the election on Monday of Timothy Masiu.
Mr Masiu is a member of the People's Progress Party.
He polled 8337 votes, more than 2000 ahead of Joe Kim Suwamaru.
South Bougainville Open became vacant after the death of Steven Pirika Kamma in February.
Mr Masiu, a former radio journalist, had run second in the 2012 national poll.
He worked for the National Broadcasting Corporation before becoming Secretary to the Deputy Prime Minister Leo Dion.