At the entrance to the sanatorium, there is a small temple or chapel. Within the series of buildings that make up the complex, there were three pavilions for patients, another one for religious nuns, a large dining hall, a clinic, baths, a laundry room, an administrative building, a hostel, a cemetery, and even a power plant and gas-metre, in addition to a church which is currently still managed by the Jesuits.

Fontilles Sanatorium opened its doors in 1909 to care for people affected by leprosy. Over the course of 119 years, it welcomed more than 3,000 individuals who found not only medical treatment but also a home and a family. The role of Fontilles was crucial in achieving the elimination of leprosy in Spain.

The Jesuit-founded temple is dedicated to one of the Father Generals of the order, Sant Francesc de Borja. It is a small-sized building with a single nave. The façade stands out with a retable-style and neoclassical design, with an upper belfry that has no bell, as this was replaced by a circular oculus that crowns the top. The corners are made of interlocking tiles, while the façade wall is made of semi-polygonal masonry. The main entrance is arched and above it there is a triple twin window that stands out in the centre.