The Philippines is holding elections seen as a mandate for President Benigno Aquino's reform agenda.
Voters on Monday are choosing more than 18,000 officials, including local leaders, more than half of the 24-member Senate and hundreds of legislators in the House of Representatives.
President Aquino swept into power by a landslide in 2010 on a promise to fight corruption that he blames for widespread poverty.
He has scored high popularity ratings for prosecuting corrupt officials, including his predecessor, Gloria Arroyo, now in detention while being tried for alleged massive graft.
Elections in the Philippines have long been plagued by bribery, along with intimidation or violence against opponents.
Results of Monday's poll are expected in a few days.