This article was reproduced with the kind permission
of the British Broadcasting Corporation
5 November 2007, 17:59 GMT
The blaze broke out late on Sunday in a cellblock at the Varones jail housing 460 inmates, in the province of Santiago del Estero.
The fire was started by prisoners who were trying to escape, reports say.
Most of the deaths were caused by asphyxiation as the block filled with smoke, said Ricardo Daives, the justice minister for the province.
Another 10 people, including some prison guards, were treated for smoke inhalation.
The authorities say that shortly after visiting time a group of prisoners set fire to their mattresses in what looked like an attempt to cause confusion and escape.
But the fires rapidly spread to other blocks and the inmates were trapped.
The authorities have now regained control of the prison and the fire has been put out.
As news of the fire spread, inmates' relatives gathered outside the prison, demanding a list of the dead and injured and there were a number of clashes with police.
Riot police fired rubber bullets and tear gas after about 200 people tried to break through barricades blocking an entrance to the prison, the government news agency Telam reported.
A similar incident happened in October 2005, when 32 inmates were killed in the prison of Magdalena, south-east of Buenos Aires, in a fire started during an uprising.