The Cathedral of the Sacred Heart of Oran is a Roman Catholic church located in Oran, Algeria. It was designed by Albert Ballou, architect of the Government of Algeria, the firm of Auguste and Gustave Perrett. The building has a Roman and Byzantine architectural style, with oriental decoration, and the church structure itself is of reinforced concrete, making it the first church built in this way. This cathedral was built between 1904 and 1913, and opened in 1918, but after Algeria's independence it was neglected until 1984, when the authorities turned it into a regional library, and then a public library in 1996.