Inside, the cathedral is a one-aisled church of rectangular shape, without transept and with a very shallow main chapel. The interior of the church, similar to its frontispiece, is lined with "lioz" stone from Portugal. The side walls of the church have a series of lateral chapels decorated with altarpieces. This floorplan scheme is based on the Church of São Roque in Lisbon, the Jesuit church of the Portuguese capital, built a century earlier. The nave of the church has a deep central altar, two lateral chapels, two chapels at the transept, and three chapels at each side of the nave. The chapels were constructed at different times and reflect numerous architectural periods and styles.