Burn victims and those who inhaled toxic fumes continued to die in the days and weeks following. Three weeks on, 61 people are still recovering in hospitals across the city. There are 28 who remain in intensive care units.
There had been up to three times as many people in the club than its 1037 capacity. The emergency exits had been locked. The disco hadn't been inspected for a year and it had caught fire twice already in 2004.
The latest victim was 21-year-old Mariana Silotta Singer, who died on 13 January. She was the girlfriend of Patricio 'Pato' Santos Fontanet, the lead singer of Los Callejeros.
The band, the rising stars of the Buenos Aires slums, had played just one song that night before the tragedy happened.
Mood of anguish
It was Argentina's worst disaster since the Benavidez train crash which killed 250 in 1970.
Masses are still being held in remembrance of the dead. More than 50 were teenagers, a dozen were under 12 years old.
The youngest victim was a 10-month old baby, Luisiana Aylen Ledesma. There had been a makeshift nursery set up in the women's toilets. A four-year-old boy, Nico, is missing and the focus of a nationwide search.
Some 191 young people died in
the 31 December disco inferno
In a mixed mood of anguish, despair and anger, a series of large street protests have taken place over the last three weeks, demanding the resignation of the Buenos Aires mayor, Anibal Ibarra.
"It wasn't a firework, it wasn't rock'n'roll, our children were killed by corruption," is the popular chant.
Friends and families of the victims have set up a protest camp in front of the club - a huge shrine of flowers, candles and messages of sympathy.
The club's owner, Omar Emir Chaban, 52, remains the only detainee following the tragedy. Expected to be charged with manslaughter, he faces up to 25 years in prison. On 18 January he was transferred to a maximum-security jail and placed in isolation.
The club front today is a shrine of
flowers, candles and messages
But victims' families who met with the minister of the interior, Anibal Fernandez, on 17 January, declared that the city government was "totally responsible" for what had happened.
Buenos Aires Mayor Ibarra has refused to go despite huge pressure. Juan Carlos Lopez, the city justice and security chief resigned within hours of the tragedy.
Argentineans are split over who to blame - the fan who let off the firework, Chaban, Ibarra or their society.
Ariel Greco, 35, manager of a public phone business, said: "Even when I was a little child I learnt it would be dangerous to let off a firework in my house. Whoever did that was incredibly stupid."
He added: "But Argentinian society is complex, we need other people to blame, even ourselves."
"Everyone knows that inspections don't happen. People look the other way for money. All the city's clubs have been closed since the tragedy," Rominha Lopez, 21, out with her friends looking for somewhere to dance, said.
Old wounds from the popular protest which ousted president Fernando de la Rua in December 2002 have been reopened, undermining a renewed confidence in the country and its popular president, Nestor Kirchner.
A banner outside government's
Pink Palace reads 'Murderers'
But Kirchner has remained politically unscathed despite early criticism for remaining on holiday until four days after the tragedy without making a statement.
He only spoke for the first time in public exactly two weeks after the tragedy, saying the government would "fight for justice and against impunity".
This week new sound recordings and video evidence emerged to add to witnesses' statements for prosecutors to try and reconstruct what happened.
Up to 3000 people had paid 10 pesos each (US$3) to get in to the Republica Cromanon club in the rundown Once neighbourhood in the centre of the capital on 30 December.
The disco, tucked away on a backstreet near the metro station, was run by Omar Emir Chaban, a flamboyant self-styled "mediocre genius", promoter of the underground rock scene and creator of the legendary club Concreto in the 1980s.
Fans had begun to follow rock bands with the same famous fervour as their prize football clubs, River Plate and Boca Juniors. They mimicked the same culture of violence against rival bands, tribal tattoos, flags - and fireworks.
Reading condolence messages on
Republica Cromanon club's walls
First came Redonditos de Ricota and La Renga and then, Los Callejeros.
Before the gig began, an unnamed producer appealed to the crowd not to throw fireworks to avoid a repeat of a "massacre" which had killed more than 420 in a shopping mall in neighbouring Paraguay just a few months earlier, in August 2004.
Arriving on stage at 10.35pm local time, the band's lead singer "Pato" asked the crowd: "Are you going to behave well?"
At 10.40 the band began to play their first song and Chaban left the club for his home on the same street.
'Open the doors!'
Just minutes into the song, a firework was set off. In a sound recording of the event, which emerged on the internet this week, a loud explosion is heard and the music is cut. There are screams and someone shouts: "Open the doors! Open!"
Three weeks on, the mood is still
one of pain, anguish and anger
The club being on two levels, people ran upstairs but this level had no exit, only bathrooms. Most people were trampled to death or died from toxic gas inhalation.
Firefighters and ambulance workers arrived quickly. Distressing images of half-naked survivors receiving oxygen and lines of bodies on the streets, their faces covered by bin-liners, began to be relayed live on TV.
At 12:40am minister of the interior, Anibal Fernandez, arrived. At 5am, Chaban was arrested.
The club had caught fire just a week before. None of the fire extinguishers were working according to staff who had used buckets of water to stem the flames.
The band Los Callejeros have not made any official comment but drummer Eduardo Vazquez, who lost his mother, said: "All the band feel a lot of guilt and a lot of pain for what has happened."