Cape Verde's governing party, the African Party for the Independence of Cape Verde (PAICV), has won Sunday's parliamentary elections.
President Pedro Pires will stand for re-election next month
With almost all votes counted, the PAICV had gained 52% of the vote, while the main opposition party, the Movement for Democracy, had 42%.
Voter turnout was as low as 58%. The new parliament will hold office for a five-year term.
The PAICV has ruled the Atlantic archipelago continuously since 2001.
The PAICV first came to power under a one-party system upon independence from Portugal in 1975.
The Movement for Democracy won the first multi-party elections in 1990 but the PAICV regained office in 2001.
"I thank voters for having confidence in us by voting massively for the PAICV," Prime Minister Jose Maria Neves said.
"It is obvious that we have not been able to do everything in a five-year term but by renewing your confidence in us you push us to do more."
During campaigning, Movement for Democracy leader Agostinho Lopes accused the government of not doing enough to boost the economy.
On Monday Mr Lopes admitted that while not all results were in, voting trends were favouring the PAICV.
"If this is confirmed I personally congratulate the PAICV," the opposition leader said.
President Pedro Pires will be standing for re-election in a separate presidential poll on 12 February.