Costa Ricans pick a new president Sunday from a field of four candidates, none of whom have a clear lead in the polls, and with nearly a third of voters undecided.
Some 3.1 million will choose a successor to President Laura Chinchilla, the country's first female president, as well as new members of congress, for a four-year term.
Long considered the "Switzerland of Central America" for its peaceful and stable democracy, Costa Ricans have endured a string of corruption scandals during Chinchilla's time in office.
Johnny Araya, mayor of the capital San Jose for more than two decades, is hoping to keep the ruling right-wing National Liberation Party (PLN) in office for a third consecutive term.
"We are confident," the 56-year-old said as he and his wife went to cast ballots in a San Jose polling station accompanied by supporters, vowing to "win in the first round."
Polls, however, show that an upstart leftist candidate, 36-year-old Jose Maria Villalta, could bring the left to power for the first time ever in this conservative, largely Roman Catholic country.
Villalta, a legislator and environmental activist, is a candidate for the leftist Broad Front (FA).
"We have a great opportunity today," he told reporters early Sunday as he took a jog around his neighborhood and bought bread for his family's breakfast.
"We can have a surprise. Let's go for change," he said.
Rivals accuse Villalta, who is attracting the protest vote, of being a communist and of supporting abortion and gay marriage.
And local media reported death threats three days ago against the young candidate, citing judicial sources, who added that his security entourage had been reinforced.
An unpredictable outcome
Polls show almost equal support for two other candidates -- historian Luis Guillermo Solis, 55, with the centrist Citizen Action Party (PAC), and businessman Otto Guevara, 53, with the conservative Libertarian Movement (ML).
They also indicate that 30 percent of voters are undecided, and that none of the candidates have more than 40 percent of support, making an April 6 runoff likely.
And yet "it's not possible to assert anything with certainty," sociologist Manuel Rojas told AFP.
"There is a 75 percent possibility of a runoff vote, but there is still a margin for Araya to narrowly make it" to the 50 percent threshold, he said.
Araya is being held down by his association with Chinchilla, who has led the least popular government in the past 20 years.
"I came to vote with the hope that there is change," said housewife Iris Rodriguez, 45, who called on the next government to "think a little about the poor."
Leftist Villalta, a lawyer, has campaigned on a platform of fighting corruption and social equality in development, successfully positioning himself as the anti-Chinchilla candidate.
But as the campaign wound down, the political polarization gave a boost to Solis as a centrist option -- making the results difficult to predict.
"Whoever wins will head a weak government," Rojas said. "They will have to gain political legitimacy through their actions. They will not be able to govern only with their party, as has been past practice."
Voting began at 6 am (1200 GMT) and is scheduled to end at 6 pm (0000 GMT Monday). Election officials say they expect to have the first official results two hours later.