Firefighters were called to the 9200 block of Wakefield Ave., north of Nordoff Street, at 4:36 a.m. where they encountered flames coming from one unit of the two-story building and extending into a second unit, according to the Los Angeles Fire Department.
It took 70 firefighters 43 minutes to extinguish the heavy flames.
"Sadly, one patient (adult female) was beyond medical help and determined dead on scene," the LAFD said in a statement. The deceased woman was not immediately identified.
A 25-year-old man, an 83-year-old woman and another man whose age was not given were taken to hospitals in unknown conditions, the Fire Department said.
Firefighters were able to prevent the fire from extending to a third attached home.
The cause of the fire was unknown. Per protocol, LAFD arson investigators were responding to the scene to investigate, LAFD spokeswoman Margaret Stewart said.