With some 90 percent of ballots counted on Sunday, the far-right libertarian economist Javier Milei had 30.5 percent of the vote, according to unofficial results, a share far higher than predicted.
The main conservative opposition bloc was behind on 28 percent and the ruling Peronist coalition came in third place on 27 percent.
The result is a stinging rebuke to the centre-left Peronist coalition and the main Together for Change conservative opposition bloc, with inflation at 116 percent and a cost-of-living crisis leaving four in 10 people in poverty.
“We are the true opposition,” Milei said in a bullish speech after the results. “A different Argentina is impossible with the same old things that have always failed.”
Voting in the primaries is obligatory for most adults and each person gets one vote, making it in effect a dress rehearsal for the October 22 general election and giving a clear indication of who is the favourite to win the presidency.
Discontent is widespread in Argentina, with the economic crisis leaving many Argentines disillusioned with the main political parties and opening the door for Milei, who attracted support by calling for the country to replace the peso with the United States dollar.
The 52-year-old politician is an admirer of former US President Donald Trump and has said that Argentina’s Central Bank should be abolished. He has also said climate change is a lie, characterised sex education as a ploy to destroy the family and said he would make it easier to own handguns.
At Milei’s electoral headquarters in downtown Buenos Aires, party leaders were ecstatic while people celebrated outside, expressing optimism that their candidate’s support would only grow in the run-up to October.
“I’m very happy, we’re looking for a change. We’re tired of living like this,” said 19-year-old Franco Lesertessur, “All the countries that have been dollarized ended up moving forward and stopped having inflation.”
The results “reflect people’s fatigue on the political leadership and the lack of solutions within the spaces that have been in power consecutively,” said Mariel Fornoni, the director of Management and Fit, a political consulting firm.
Fornoni said that during the campaigns, the political establishment was “focused on their own group dynamics rather than addressing the actual needs of the people”.
In the main opposition coalition, Together for Change, voters also appeared to be ready to move more to the right as former Security Minister Patricia Bullrich handily beat a more centrist contender, Buenos Aires Mayor Horacio Rodriguez Larreta.
Bullrich made clear she would work with her competitor ahead of October.
“As Argentines we live with distress, with fear, unable to dream, plan or live a normal life. But today we have reasons to work together, to guide and lead a profound change in Argentina, a change that leaves corruption behind forever, paving the way for austerity,” Bullrich said.
The governing coalition, Union for the Homeland, meanwhile, took a beating from voters over the poor state of the economy, finishing in third place for total votes.
As expected, Economy Minister Sergio Massa became the coalition’s presidential candidate, easily defeating leftist Juan Grabois.
“We have 60 days to turn this election around,” Massa told supporters.
Turnout on Sunday was under 70 percent, the lowest for a primary election since they started to be held in Argentina more than a decade ago.
Whoever wins in October, or more likely in a November run-off, will have big decisions to make on rebuilding depleted foreign reserves, boosting grain exports, reining in inflation and on how to unwind a thicket of currency controls.
Jorge Boloco, 58, a merchant, said Argentina needs a “course into the future”, but that no party offered a clear way forward.
Maria Fernanda Medina, a 47-year-old teacher, said she had also lost some optimism about politicians truly bringing change after many years of revolving economic crises.
“I don’t have much hope because, in every election, I feel a little disappointed,” she said as she cast her ballot in Tigre, on the outskirts of Buenos Aires.
“But hey, we can’t lose all hope, right?”