Mr Alfonsin was the first democratically elected president after military rule
Argentina's first president to be democratically elected after the "Dirty War" military dictatorship, Raul Alfonsin, has died of illness aged 82.
He had suffered from pneumonia and lung cancer and last appeared in public in October, when the current president unveiled a bust in his honour.
A medical team had been tending to him at his home in Buenos Aires.
Mr Alfonsin was elected president in 1983, after the fall of the military regime which had held power since 1976.
Critics point out that he failed to stave off a deep economic crisis but his political achievement was summed up by current President Cristina Fernandez, when she unveiled his bust last year.
"Whether you like it or not, you are a symbol of the return of democracy," she said.
While the junta was in power, Mr Alfonsin stood as a prominent opponent of their actions.
As president, Mr Alfonsin won international admiration for putting on trial and jailing former military officials who had tortured and killed thousands of suspected leftists.
Six years after taking office, he completed Argentina's first transfer of power from one elected president to another in decades.
However, his centrist Radical Party, discredited for its handling of the economy, was crushed at the polls by Peronist leader Carlos Menem.
Inflation had hit a record 200% per month and the poverty rate had more than doubled under his rule to above 25%, while the currency lost 95% of its value inside four months, Reuters news agency recalls.
"No president has the right to endlessly demand sacrifices from his people," Mr Alfonsin told Argentines by television as he stepped down in 1989.
'Brave and determined'
The BBC's Candace Piette in Buenos Aires says family members, political figures and friends have gathered outside Mr Alfonsin's house to pay their respects, some lighting candles and weeping.
For many Argentines, the former president was a brave and determined man, our correspondent says, who did not take the easy road.
A lawyer by profession, one of his first acts as president was to begin the process of trying the military for human rights abuses.
He was partially successful, despite their resistance and their threats, our correspondent says, and by the end of his government many of the top members of the military had stood trial.