The fire occurred at about 4:57 a.m. local time (1957 GMT Sunday) on the third floor of the 27-story apartment building in Seoul, Yonhap news agency reported.
Two men in their 30s and a woman in her 70s were taken to hospitals in cardiac arrest, two of them died later.
During the evacuation, 28 people suffered injuries, such as smoke inhalation, and 20 of them were taken to hospitals for treatment.
The fire was completely extinguished around three hours later as the fire authorities sent 57 vehicles and over 200 personnel to the scene.
The police and the fire authorities were investigating the cause of the incident.
AMK/PR