On entering the Cathedral, there are three doors that face the Arms Square, engraved in cedar wood, which are believed to date from the start of the XIX Century. The floor is made of ceramics forming geometrical figures.

The Great Pipe Organ is located over the atrium, custom manufactured in London by the Flight House Company entrusted by the Archbishop of the time, Rafael Valdivieso. He arrived to Chile in December 1849 and the organ was played for the first time during the 1850 Holy Week.

In the central nave, many changes made to the Cathedral by Ignacio Cremonesi can be seen. He built a flat slab vaulted ceiling, covered in plaster and abundantly adorned with moldings, cornices, medallions and illustrations from biblical scenes, strongly influenced by Italian artists. Additionally, in some sectors and in the details marble paint is used.

Hanging above the pillars of the central nave are the images of Prophets and Apostles, illustrating the union of two Christian-faith alliances. This imagery is carved in wood and is fire gilded, ordered from France in 1850 by Archbishop Valdivieso (another version mentions that they were carved in the Jesuit workshop located in Calera de Tango in the XVIII Century, with a Bavarian Baroque Style).

We must also mention the two pulpits adjacent to each end of the central nave, with gold-leaf appliqués, in a neo-classical style, manufactured during the first half of the XIX Century. These were previously used to preach the Gospel and read the Epistles.

The central nave ends in the Presbytery, where the high altar, the Catedra and the priests’ meeting space are located. Towards the back it all comes together with an altar piece, which has the image of the Ascension of the Virgin, center stage, with her arms opened wide, surrounded by angels. To the right there is the image of Santa Rosa de Lima, Patron Saint of the Americas, and to the left the image of Apostle Santiago, Patron Saint of the city of Santiago. The entire ensemble is French in origin, imported in 1865, and made out of polychrome and gilded wood.

Beside the choir, on the left pillar is the bronze crucifix donated by Pius IX to the Cathedral.
The high altar, located towards the back of the central nave is made with white marble, with stone appliqués and bronze ornaments and a large shrine welcomes and outstands to exhibit the Holy Sacrament. This valuable altar was built in 1912 by the Mayer House Company in Munich. The altar is crowed with a pelican, the symbol of Christ’s love for His Church. In front of the shrine is the Lamb of God, symbol of Jesus Christ, when he gave Himself in sacrifice, crucified on the cross.

In front of the altar there are some wood carved benches where priests seat. They were made out of mahogany by the Bavarian Jesuits of Calera de Tango during the XVIII Century. Located to one side is the Cathedra . It’s a canopy made of carved gilded walnut wood also ordered by Archbishop Rafael Valdivieso, during mid XIX Century.

Between 2005 and 2006 the altar was remodeled along with the archbishop’s crypt located under the high altar, where the human remains of Bishops and Archbishops of Santiago rest. It was created by the architects Sebastián Bianchi, Patricio Mardones and Rodrigo Pérez de Arce. The image of a crucified Christ is located in this area made of polychrome wood and one of the Pietá is made of ivory, both of them carved in a romantic style.

Behind the high altar, the naves are interconnected because they do not have an apse. In this area we also find the Diego Portales crypt that has a marble tombstone.

Finally, over the high altar you can see the richly ornamented circular dome preceded by two beautiful stained glass windows made by the Munich Mayer Company in Germany (1905-1912), ordered by Cremonesi. Both stained glass windows are in a Renaissance style and the technique used is that of painted and furnace-heated glass, horizontal with an extended arch and is excellently preserved. One of them shows Christ and His Apostles and the other shows Christ and His Church, where several saints can be identified.

The lateral naves have the ceiling built in such a way that they generate small domes separated by semicircular arches and ornamented with gilded moldings. The domes are painted in light blue and golden details, simulating a star-filled sky and as a connection with heaven.

Under each dome there is a stained-glass window, also made by the Mayer Company totaling 16 stained-glass windows (8 pieces in each nave), all in a Renaissance style using the painted and furnace-heated glass technique, horizontal with a semicircular arch. They show the portrait of a saint with his/her respective name. Most of them are well preserved and some have small restorations.

Further down there is an altar or monument.

South Nave (going through the main entrance)

– Access to the Parrish of the side chapel with the image of the Virgin del Carmen.
– Altar of Apostle Santiago (patron saint of the city). It is a polychrome image in a European style.
– Altar of Saint Miguel Archangel. Polychrome image possibly made by the Mayer Company.
– Altar of the Virgin Dolorosa. Donated by the Hermandad de Dolores.
– Altar of Our Lady of Transit (de la Assumption). Painting.
– Access to the Chapel of the Holy Sacrament. Built by Ignacio Cremonesi. The altar is carefully ornamented (with its front made of embossed silver) made in the Jesuit workshops of Calera de Tango, dated from the XVIII Century; as well as silver objects, including a lamp dating from the XVII Century.
– Altar of Saint Joseph with Baby Jesus.
– Altar of Crucified Jesus. Image in carved polychrome wood and it is said that it was donated by King Philip II of Spain. The images of the saints are said to be the work of the Chilean sculptor, Nicanor Plaza in 1870.
– Access to the Sacristy.
– Sepulchral Monument of Monsignor Rafael Valentín Valdivieso.

North Nave (through the main entrance)

– Monument to the Heroes of the Battle of the Concepción. It is made in a neo-Gothic style in white marble dating from 1912.
– Altar of Saint Francis de Sales.
– Altar of San Francisco de Paula.
– Altar of Saint Alberto Hurtado.
– Altar of Santa Teresa de Los Andes.
– Altar of the Ascension of the Lord.
– Altar of Our Lady of Carmen (Patron Saint of Chile). It is believed that this is the work of Jacques Pilliard, dated in Rome, in 1864.
– Altar of Our Lord Jesus Christ.
– Altar of Saint Peter. Painting.
– Tomb Monument of Monsignor Joaquín Larraín Gandarillas (founder of the Catholic University of Chile).