The two-alarm blaze was reported at 5:25 p.m. on Castillo Street near Geneva Avenue, San Francisco fire Paramedic Captain Beth Goudreau said.
The fire was located at a wooden building but also impacted a neighboring building, Goudreau said.
Firefighters were able to bring the fire under control at 6:09 p.m., according to Goudreau.
One person died at the scene and five people were transported to the hospital, all are believed to be adults, Goudreau said.
Two of the victims were transported in critical condition. One person was transported with moderate injuries and two people were transported with minor injuries. An additional person complained of injury but refused to be transported, Goudreau said.
The American Red Cross has responded to the scene to assist an undetermined amount of residents who were displaced by the blaze.
The cause of the fire remains under investigation and arson investigators remain at the scene tonight.
The identity of the deceased victim has not been released, according to Goudreau.