Radio reports from Comayagua said dozens of prisoners were burned beyond recognition as they were trapped in their cells. The reports said the prison was destroyed by the flames.
Radio Globo, a station in Comayagua, said the death toll exceeded 200, but Honduran authorities would neither confirm nor deny this number.
The BBC Online said some survivors escaped the blaze by breaking through the roof and jumping from the building.
Local hospitals were treating dozens of people for burns and other injuries, a firefighters' spokesman told the Spanish news agency Efe.
Some of the injured had been taken to the capital, Tegucigalpa, for treatment.
- Agencies