The fire was reported just after 9 a.m. Monday at a Craftsman-style home in a neighborhood near Bonnie Brae Street and Pico Boulevard, according to the Los Angeles Fire Department.
Flames ripped through the building, destroying it.
Two people were rescued from the second floor, and three victims were in fair condition and declined to be taken to a hospital, according to fire officials. A firefighter suffered minor injuries.
Crews took up defensive positions, fighting the blaze from outside the structure.
The fire spread to two adjacent buildings. Crews put out the flames in one and then contended with fire in the walls of another, according to LAFD spokeswoman Lyndsey Lantz.
About 120 firefighters responded to the scene, and a knockdown was reported in one hour and 37 minutes.
The cause of the fire is under investigation.
City News Service contributed to this report.