Burundi's local councillors have elected most of the senators who will form the national parliament's upper chamber of 41 members.
Pierre Nkurunziza (l) was a PE lecturer
The election brings Burundians one step closer to choosing a new president and further away from the war between the Tutsi-dominated army and Hutu rebels.
Election officials say the FDD ex-rebels has won a huge majority.
FDD leader Pierre Nkurunziza is the only nominee to be president - he will be chosen by lawmakers next month.
The Forces for the Defence of Democracy (FDD) was expected to win after sweeping council elections and legislative elections earlier this year.
Each of Burundi's 17 provinces chose two senators - one Tutsi and one member of the Hutu majority.
Four former presidents will also have seats, along with three members of the Twa community, who account for 1% of the population.
Correspondents say one of the reasons for the FDD's success is its inclusion of many Tutsi officials within the party.
The biggest challenge for the FDD will be to bring the only remaining rebel group, the FNL into the peace process, observers say.