The polling stations began their operation at 11:00 GMT and will remain open until 20:00 GMT. The election results are expected to be announced on Sunday evening.
The main election competition will be between two presidential hopefuls- Brazil's former President Luiz Inacio Lula da Silva and incumbent Brazilian leader Jair Bolsonaro.
It is necessary to gain over 50% of votes in the first round of election for a candidate to win. If there is no winner in the first round, a runoff will be held on October 30.