The upper part of the main nave of the Santa Ana church is made of a barrel vault ornamented with moldings, but all in white.

Along the nave are positioned the marble devotional altars that mix different Graeco-Latin styles. Noteworthy are the carvings of the Sacred Heart of Jesus, Saint Joseph, Saint Joachim, among others. In addition, there are some pictorial works such as the Virgin of Guadalupe. The pulpit is also made of marble.

The stained glass windows are dedicated to different saints and biblical passages; it cannot be seen to which workshop they belong.

The nave finishes in the High Altar that has a marble reredos dedicated to the image of Saint Anne and Christ on the Cross, watched over by two angels. The communion rail is also made of marble.

In the transept area, there are also devotional altars with beautiful carvings, highlighting the image of the Immaculate Conception and that of Saint Michael the Archangel.

In the choir, there is an organ built by Oreste Carlini, possibly in 1920.

In one of the lateral chapels there is the marble baptismal font where Saint Teresa of the Andes and Blessed Laura Vicuña were baptized.