Officials say the fire started just after 9:30 p.m. Friday at the 1600 Church Road Condominiums in Wyncote, Pa.
Officials say the B-building was taking on heavy fire that quickly spread to four alarms.
More than 120 firefighters were on the scene battling the blaze. The fire was placed under control just before 3:00 a.m.
Officials say 50 units have been infected by the fire and at least 100 residents are reported to be displaced.
Five residents and two firefighters were injured. They were taken to Abington Hospital where the firefighters were treated and released.
The Red Cross has set up a shelter at Cheltenham High School for displaced residents.
No word yet what sparked the blaze.