The fire broke out in the early hours of Thursday (October 14) at a 13-story residential building in the southern Kaohsiung city.
Kaohsiung authorities told reporters via a social media chat group that at least 40 people have been killed and 60 remain hospitalized.
Footage from local television showed firefighters dowsing the burning building with water, as rescue personnel carried away residents, many in oxygen masks, on stretchers.
According to Taiwan's Central News Agency, the 40-year-old building includes around 120 households on 13 floors, at least five of which are empty. The fire was extinguished at around 07:15 a.m. local time (2315 GMT Wednesday).