Porfirio Lobo is considered the favourite to win
Presidential elections are due to be held in Honduras, five months after a political crisis ousted President Manuel Zelaya.
He was forced from Honduras at gunpoint in June, and replaced by Roberto Micheletti. They are not candidates.
The favourite to win is conservative Porfirio Lobo from the National Party, and Elvin Santos from the Liberal Party is considered his nearest rival.
Mr Zelaya's supporters have called on voters to boycott the election.
Mr Lobo, 61, narrowly lost to Mr Zelaya in 2005, and Mr Santos, 46, was previously Mr Zelaya's vice president in the divided Liberal Party.
Polling stations are due to open at 0700 (1300 GMT) and close at 1600 (2200 GMT).
About 30,000 soldiers and police are to provide security for the elections, but many fear violence could erupt.
The political crisis and election have divided the region, with the US indicating it would endorse the result if the elections are deemed "free and fair".
Costa Rica, which has long been the mediator between the two sides in this crisis, has said likewise, but other Latin American countries have opposed the vote.
Soldiers have been brought in to ensure security
Argentina and Brazil have said they will not recognise any government installed after the election, arguing that to do so would legitimise the coup which ousted an elected president, and thus set a dangerous precedent.
The main regional grouping, the Organisation of American States, has declined to send an observer mission.
BBC correspondent Stephen Gibbs in the capital Tegucigalpa says that while supporters of Mr Zelaya are watching events with dismay, many Hondurans are expressing optimism that an end to this country's political crisis is in sight.
Congress is due to vote on Mr Zelaya's reinstatement on 2 December. His term ends on 27 January.
Mr Micheletti temporarily stepped down from office - for a week until 2 December - to allow the elections to proceed "peacefully and transparently", his spokesman said.
Mr Zelaya was sent into exile on 28 June after trying to hold a vote on whether a constituent assembly should be set up to look at rewriting the constitution.
His critics said the vote, which was ruled illegal by the Supreme Court, aimed to remove the current one-term limit on serving as president and pave the way for his possible re-election.
Mr Zelaya has repeatedly denied this and some commentators say it would have been impossible to change the constitution before his term in office was up.