Guinea-Bissau's former ruling party, the PAIGC, has won a clear majority in last Sunday's parliamentary polls, the election commission says.
The party which ushered in the West African nation's independence in 1974 took 67 seats out of 100, BBC reports.
International observers hope the successful election and clear mandate will bring stability to Guinea-Bissau.
The former Portuguese colony has had a history of coups since independence, and has become a drug-smuggling hub.
The BBC's West Africa correspondent Will Ross says for many months no single party had held a parliamentary majority in Guinea-Bissau.
This had led to ineffective coalitions which were plagued by acrimony and splits.
In recent years, Guinea-Bissau has become a major transit point for South American cocaine headed for Europe.
The international community has been worried that without effective political leadership it is in danger of becoming a narco-state with drug barons holding more power than the politicians and the rule of law.
But the elections passed off smoothly without violence - in contrast to previous polls.
Our correspondent says the people of Guinea-Bissau will hope that a corner has been turned and the politicians, instead of fighting, will start to make some headway in the fight against poverty.