The Pasadena Fire Department responded to a call shortly after noon on Wednesday at the Salvation Army at 56 W Del Mar Blvd.
Firefighters went into a defensive mode to fight the two-alarm blaze which started from cardboard boxes behind the facility.
According to a city spokesperson, more people are making donations at the facility since it reopened.
Over 30 fire personnel were on scene to fight the blaze. No one was injured in the fire.
The fire was extinguished about an hour later.