SÃO PAULO—Brazilian incumbent President Dilma Rousseff of the center-left Workers’ Party has been re-elected for a second four-year term, with 98.13% of the votes counted in the country’s presidential runoff.

According to Brazil’s electoral court, Ms. Rousseff has garnered 51.45% of the votes so far, while Aécio Neves of the conservative Brazilian Social Democracy Party has 48.55%.

Ms. Rousseff took office in January 2011. Her second term will finish in December 2018.

In first-round voting, on Oct. 5, Ms. Rousseff received 41.59% of the votes, while Mr. Neves received 33.55%. Marina Silva of the Brazilian Socialist Party came in third with 21.32%.

Write to Rogerio Jelmayer at rogerio.jelmayer@wsj.com and Luciana Magalhaes at Luciana.Magalhaes@dowjones.com