To the left of the altar, high on the wall, is a huge architectural cross. Light pours through alabaster into the church along the slanted crossbeam. The cross is the emblem of Christ, "the Light of the world." The place behind and to the left of the Altar is the Presbyterium, where the priests gather around the Bishop to concelebrate the Liturgy. It can hold 400 priests.

This vast space also accommodates many risers allowing choral groups to perform. The Los Angeles Master Chorale, Philharmonic and others will perform sacred concerts in the Cathedral.

Two transepts on either side of the Sanctuary allow the assembly to gather around the altar. This cruciform structure is traditional in Catholic churches and represents the cross on which Jesus died.