The fire was reported at about 6:15 a.m. at a three-story apartment building at 640 E. 15th St., Battalion Chief Melinda Drayton said.
Roughly 40 firefighters responded and rescued five adults and two children from the upper floors, Drayton said.
One adult and the two children were transported to hospitals for treatment of smoke inhalation and minor injuries, she said.
The fire was controlled in about an hour. It appears to have started the building's basement, and caused about $250,000 in damage, Drayton said.
The cause remains under investigation.