It is a Renaissance building built in the 16th century. It is freestanding and consists of two distinct parts: the Chapel and the Hospital, although both share the same roof.
The Chapel has a rectangular plan and can be seen from both sides. The parapet is made of stone and is very well ventilated. They form the walls, which have few gaps. The upper part ends with triglyphs and metopes around the entire perimeter. There is a molded cornice above the frieze. This supports the roof and does not have an eaves. The facade that opens onto the church square has an opening axis with an entrance and a semi-circular arch. It has simple moldings. The axis ends with a stone bell wall and the bell is inserted inside an opening.
The facade that appears on Donibane Street is asymmetrical. The portico is notable; it has a semi-circular arch and is supported by two Doric columns. The entablature is made up of triglyphs and metopes. At the end of the portal is the image of Saint John, inserted into the niche. At the top is a pediment and on the sides are volutes. In addition, the coat of arms from the 18th century can be seen. It is well preserved. On the right is the entrance with two windows. The windows are designed to keep out the wind and dust. Inside, there is a cross vault to cover the square floor plan and it is also quite complex. The grooves are painted pink. Both the walls and the masonry fittings of the vault are whitewashed. It can be accessed from all sides except the top. In addition to those mentioned, there is a doorway-like blind in the gospel.
In the front part, a 17th-century Renaissance altarpiece can be seen. It is made of polychrome wood. It was almost certainly made by Jeronimo de Larrea. The statue of Saint Sebastian and the “Afflicted Christs” from Azpeitia have a great deal of stylistic coherence. Larrea mentions both of them in his will. The altarpiece was probably made after 1595. The altarpiece is classical and has the simplicity of the period. It has a pew, two bodies and three aisles. The niches support six statues. In addition, there is a roof for the Calvary. The Calvary is protected by two figures: the Archangel Saint Michael and the Evangelist Saint John. The frieze that separates the two floors contains reliefs of the Burial and Resurrection of Christ. In the central aisle, the niches represent the titular Saint John the Baptist and the Virgin with Child. The others are statues of saints. There is also a crucified Christ. According to Lekuona, it is Gothic and comes from the Andrearriaga hermitage.
The hospital building is a complex building and is attached to the religious building. It has three heights and the openings and niches are surrounded by ashlars. As a result of the latest renovation, another floor was built under the roof. The two bodies are structured by a brick wall and wooden observatories. A large and beautiful Baroque coat of arms has been added to the rear facade. The coats of arms of the estates of Zuloaga and Oiartzabal are shown.
