Dilma Rousseff received about 41% of the vote and is set to face a run-off against centrist Aecio Neves, who got 34%, near complete official results show.
SHAFAQNA – Brazilian incumbent Dilma Rousseff has won most votes in the country’s presidential election, but has fallen short of outright victory.
Analysts now predict a potentially tight second round on 26 October.
The socialist candidate, prominent environmentalist Marina Silva, finished third with 21%, and is out of the race.
More than 142 million were eligible to vote on Sunday. Turnout was 80%. Voting is mandatory for those aged between 18 and 70.
Brazilians also elected members of congress and regional governors on Sunday.
Early in the campaign, incumbent Ms Rousseff – from the left-wing Workers’ Party (PT) – had been expected to win outright.
However, the death in an air crash of Socialist Party candidate Eduardo Campos had a major effect on the race when he was replaced with Ms Silva.
Last month she was riding high in opinion polls and appeared likely to reach a second round. However her popularity later slipped.
The election results have surprised many in Brazil, the BBC’s Julia Carneiro in Rio de Janeiro says.
In the end, most people voted for traditional parties – the PT and Mr Neves’ Social Democrats. She adds that the main issue now is who can be trusted to revive the economy.
During Ms Rousseff’s tenure as president, unemployment has been lower than under any of her predecessors, at about 5%. The minimum wage has risen and the number of undernourished Brazilians has been falling.
But the past 18 months have been marred by recession and corruption scandals, and protests over poor public services and the World Cup costs.
Source: BBC News