The election has pitted Castillo, a little-known elementary school teacher, against Keiko Fujimori, the daughter of jailed ex-President Alberto Fujimori.
The first round of the election was held on 11 April. The first exit polls published indicated that underdog nominee Pedro Castillo of Free Peru had placed first in the first round of voting with approximately 16.1% of the vote, with Keiko Fujimori with 11.9%.
According to opinion polls, the right-wing candidate Keiko Fujimori is slightly ahead of leftist Pedro Castillo, by a 0.7 percentage point margin.