The fire broke out about 1 p.m. EDT at St. Mary the Protectress Ukrainian Orthodox Church. About 125 firefighters got the fire under control by 3:19 p.m.
Philadelphia Fire Commissioner Lloyd Ayers said he called crews out of the structure just before the roof caved in, WCAU-TV, Philadelphia, reported.
The Preservation Alliance for Greater Philadelphia says St. Mary -- one of several Orthodox churches in Philadelphia -- was built in 1914 by the Oak Land Baptist Church, and is classified as a "historic religious property."
The congregation of about 100 people is mostly made up of Greek and Ukrainian immigrants, a church member told the TV station.