A fire occurred at Guryong village in Gaepo district, southern Seoul, at around 2 p.m., causing 139 residents to evacuate.
Police said a 71-year-old resident was found dead around 7 p.m.
Firefighter were able to contain most of the blaze at about 3:30 p.m., and are continuing to put out the last flames.
The fire, which started at a junk shop, burned through some 900 square meters of the town, including some 60 residences in 16 unauthorized housing structures.
Most residents evacuated to a nearby middle school. Guryong village was formed in 1988 as an unlicensed residential community, with over 1,000 low-income households residing in clustered shacks and makeshift buildings.