Argentines have voted for their next president, bringing a curtain down on 12 years under power couple Nestor and Cristina Kirchner.
Their heir apparent, Buenos Aires provincial Governor Daniel Scioli, is poised to win but may undo parts of "kirchnerism," a populist creed built around trade protectionism, social welfare and defence of the working classes.
The 58-year-old powerboating fanatic - who lost his right arm in a 1989 racing accident - served as Nestor Kirchner's vice president.
He has vowed to uphold the core of the Kirchners' legacy, but has also promised a change in style to attract more investment and increase productivity.
His top rival is Buenos Aires Mayor Mauricio Macri, the candidate of Argentines fed up with what they see as the Kirchners' heavy-handed economic policy and belligerent politics.
Macri, 56, rose to prominence as the boss of Argentina's most popular football club, Boca Juniors, which won a string of titles under his reign.
There may also be a spoiler in the form of Sergio Massa, a former Kirchner ally who fell out with the president and launched a rival party, the Renewal Front, two years ago.
Under Argentine electoral law, in order to win outright in the first round, a candidate must claim more than 45 per cent of the vote, or at least 40 per cent with a margin of 10 points over the runner-up.
Opinion polls put Scioli at about 40 per cent, with Macri at around 30 per cent and Massa around 20 per cent - roughly the same scores seen in the August primary.
That means the country could be headed for its first-ever run-off election, on November 22.
Nestor Kirchner came to office in 2003, in the aftermath of a devastating economic crisis that triggered what was then the largest sovereign debt default in history.
He presided over a stunning turnaround underpinned by average economic growth of more than eight per cent a year.
He handed power to his wife in 2007 and died of a heart attack in 2010.
Cristina, a fiery former senator, won re-election in 2011.
As she cast her ballot on Sunday, the 62-year-old leader said she was proud to be handing over a "normal" country.
"In the past, we've always voted in the middle of crisis," said Kirchner, who leaves office with an approval rating of around 50 per cent after serving the two-term limit.
But the economic magic of the early Kirchner years has faded.
When Argentina's next president takes office on December 10, he will inherit a country troubled by inflation, an overvalued currency and an economy facing what the International Monetary Fund predicts will be a 0.7 per cent contraction next year.
Argentina's 32 million voters, who are required to cast ballots, are also electing their representatives in Congress and regional bloc Mercosur.
Pollsters have warned the numbers are so close that counting could stretch well into Sunday night.