It has two different parts: the main chapel - built by Fernando de Andrade in 1538 - and the rest of the church, the work of Archbishop Rajoy at the end of the 18th century.
In the main chapel, the intricate ribs of the vault and the Renaissance altarpiece from 1561 stand out.
The image of Santiago Apóstol that is in the central area of the altarpiece was buried in the presbytery in 1961 when some work was underway.
The rest of the church is organized on a Latin cross plan with poorly marked arms and three naves, of which the central one is covered by a barrel vault.
It is made up of three "streets", two canvases were torn from the central one to place the tabernacle and the image of the patron saint, Santiago.
On the façade there are three doors, the central one is crowned by the coat of arms of Fernando de Andrade, an equestrian statue of Santiago Apóstol and a plaque of the Heart of Jesus with his motto "I will reign in Spain", placed in 1900 to commemorate the beginning of the century.
In its upper part there are still allusions to the heraldic emblems of the Andrade family.
On the Gospel side is the tomb of Fernando de Andrade where he was moved from the center of the chapel in 1758.