Polls opened across Brazil at 8 am local time on Sunday as voters began casting ballots in a closely contested presidential runoff between incumbent Luiz Inacio Lula da Silva and conservative Senator Flavio Bolsonaro.
The election pits 80-year-old Lula of the Workers' Party against 45-year-old Bolsonaro, the eldest son and political heir of former President Jair Bolsonaro.
The runoff follows a competitive first-round vote on October 4, when Bolsonaro led with 47 percent of valid votes against Lula's 45 percent. Neither candidate secured an outright majority.
The contest enters election day in a statistical dead heat, with a Datafolha poll showing both candidates tied at 50 percent of valid votes.
The election has centred on the rising cost of living, public insecurity and persistent corruption concerns affecting Brazilians' daily lives.
Lula, who governed Brazil from 2003 to 2010, returned to power after defeating Jair Bolsonaro in the 2022 presidential election by less than two percentage points.
The victory marked the narrowest presidential margin in modern Brazilian history. Lula is now seeking a fourth nonconsecutive term.
Flavio Bolsonaro entered the race after his father was barred from holding public office and sentenced to 27 years in prison following investigations into a planned military coup after his 2022 defeat.
The former president's political base remains strong, with his wife, Michelle Bolsonaro, securing a seat in the Federal Senate during first-round voting.
A victory for Flavio Bolsonaro would mark a return of the right in Brazil and align the country with a broader conservative shift across the region linked to the Trump administration in the US.
More than 150 million registered voters are expected to cast their ballots electronically across Brazil's 26 states and the Federal District.
Preliminary results are expected shortly after polls close at 5 pm Brasilia time.
