Here are key facts about the elections:
* A total of 50,086,054 registered voters as of January 2010 are eligible to vote at 80,000 clustered polling precincts in 80 provinces across the archipelago. Each precinct has an average of 1,000 voters. The country has a population of about 92 million, with nearly a third classified as poor.
* Voters will elect a president, vice president, 12 senators, 230 representatives and 57 party-list positions in the lower house of Congress, 80 governors, 80 vice governors, 766 members of provincial legislative boards, 137 city mayors, 137 vice mayors, 1,524 city councillors, 1,497 municipal mayors, 1,497 vice mayors and 11,980 municipal legislative positions.
* Voters will use a special pen to shade blank dots beside the names of the candidates instead of writing down candidates' names as before. An ordinary ballot would include an average 600 names of candidates for local and national positions.
* Ballots with erasures and extra markings will not be accepted by the counting machines. The election agency is not printing extra ballots for voters who make mistakes in casting their votes.
* The counting machines will automatically generate a tally of votes, which will be transmitted to servers at municipal, provincial and national election offices. Printed copies of the returns will be shared with the two major political parties, and an election watchdog headed by a church-based group will do a parallel quick count.
* The election returns from polling precincts, transmitted electronically, will be canvassed by a board at the municipal, city, provincial and national levels. Results are expected within 2 hours at the local levels and 36 hours at the national level.
* At the end of canvassing, the winners at the provincial, legislative, district, city and municipal elections will be proclaimed.
* The Commission on Elections (Comelec) in Manila will proclaim winners in the senatorial and party list election. A joint session of Congress will announce winners in the presidential and vice presidential elections. Comelec estimates the election period will end on June 9.
* Elections are usually marred by vote-buying, cheating, threats and intimidation by political groups. In previous elections, authorities have received hundreds of complaints about discrepancies in the list of voters, such as missing names and the illegal transfer of voters to other polling precincts.
-- For more data, see the Commission on Elections website (www.comelec.gov.ph)