The fires broke out in a shoe factory in Lahore, Pakistan's second-largest city in eastern Punjab province, and in a garment factory in Karachi, the country's largest city and its main port and financial center.
Pakistan's News International newspaper said the two fires together killed at least 62 people and injured 51 more.
The Lahore shoe plant fire, in which 22 workers reportedly died, broke out after an electricity generator caught fire and flames immediately engulfed chemicals at the facility, the News reported. Firefighters had to knock down a wall to retrieve the bodies.
The Daily Times reported some of the dead were so badly charred that identifying them was posing a problem. The report quoted a police official as blaming the blaze on inadequate fire safety measures.
Other reports said the owner of the shoe factory was among those killed.
The Karachi garment factory fire, whose cause had not yet been determined, killed at least 40 people, including four women, the News said, quoting a fire official. Those injured were taken to local hospitals.
The official was quoted as saying about 250 workers were at the site when the fire erupted in the evening. The report said several of them rushed to the rooftop as there was only one exit out of the building. Several of them jumped from their perch, suffering serious injuries.
As firefighters worked to put out the fire, a large boiler exploded causing the flames to spread to all floors, trapping several of the workers, the report said.
The Express Tribune newspaper, quoting a fire official, said the fire was so intense firefighters were having difficulty entering the facility.
"Right now, we are trying to get inside the factory, where we fear we will find more bodies," he said.