The church was rebuilt on the site of the shrine to San Antonio Abad in 1780 by Francisco Javier Pedrajas. Its design is based on a traditional cross, its transept dominated by a double-sectioned cross-vaulted roof and a large segmented dome: this rests on a rounded cornice, supported by an imposing array of archangels. Individual displays of delicate rococo plasterwork spread throughout the building, flooded by the natural light which streams in from the roof and dome.
The altarpiece and its supporting screens are the work of Pedrajas: it has a base, two superior levels, and a central chapel, flanked by Corinthian columns with overlapping bindings: these separate the sidepieces – housing the figures of San Ramón Nonato and San Thomas Aquinas — from the central chapel with its figure of the Virgen de las Mercedes. The second level is the image of Santa Catalina. The plasterwork and mouldings are gilded.
The main chapel with its diminutive figure of Nuestra Señora de las Mercedes is all that remains of the ancient shrine. Believed to be the work of Juan de Dios Santaella in 1753, it is square in form, with curved insets, and flanked by four angels on plinths.
The neoclassical portal with its twin pillars is in marble, by the craftsman Nicolás Duroni in 1799, however, only the first level was completed. The façade is finished off with two towers.
The church has been declared a national monument.