In 1917 a large church was completed that had a seating capacity of 1,000. In 1924, the construction of the basilica of Saint Joseph's Oratory was commenced; it was finally completed in 1967.
On October 19, 2004, the Oratory held its centennial. All the bells of all the churches on the island of Montreal were supposed to ring at 9:00 a.m., though not all churches participated.
In 2004, the Oratory was designated a National Historic Site of Canada on the occasion of its 100th anniversary.