Firefighters were called to the blaze on Queen Mary Street in Maltby, Rotherham, shortly before midnight last night.
Crews wearing breathing apparatus extinguished the flames.
They found the body of a man in his 50s inside the property.
Crews from Maltby, Aston Park and Edlington stations attended the fire, to which they were called at 11.38pm.
Chesterfield Road Sheffield: Man who spent 12 hours on roof is sentenced in court for affray and harassment
The Long Blondes: Leadmill cancel gig after allegations surface against band creator Dorian Cox
EuroMillions: Mystery winner from South Yorkshire has won £79,242.50 on The National Lottery
Sheffield Council employees sacked as fraud increases including theft and excessive internet use during work
Chapeltown Sheffield rape investigation: 16-year-old arrested over assault of girl, 13, is bailed
South Yorkshire Fire and Rescue said a multi-agency investigation into the cause of the fire would now take place.