The Spanish mission transformed life in the region, introducing domesticated animals, fruits, vegetables, and winter wheat. The current building, finished in 1783, is the oldest European-designed building in Arizona, constructed under the supervision of a Basque master mason, Ignacio Gaona. The church is built in the Roman style with twin fired adobe walls on volcanic stone foundations. The ceilings are made of vaulted adobe due to the scarcity of timber in the region. Today, San Xavier is one of the few missions still ministering to the population it was built to serve: the descendants of the Tohono O’odham people, the Pacua Yaqui who were settled into the area, and people of Hispanic and European origins, many of whom can trace their roots back to the colonial period.

San Xavier is both a pilgrimage church and a significant cultural site, hosting over 300,000 visitors annually. Patronato San Xavier, the nonprofit created to support the mission, offers visitors free guided tours and has a small museum that provides historical, architectural, and religious information about the area. For locals, the mission supports a tuition-free K-8 school, provides a variety of counseling services, and organizes numerous annual festivals and events. Recently, Patronato has begun the second iteration of its conservation apprenticeship program, which educates individuals in the art of conservation, using the mission as an educational training ground.

In the 1940s and 1950s, the exterior of the mission was covered in Portland cement, which caused the underlying original adobe to deteriorate. A $10 million campaign in the 1990s removed most of the Portland cement and financed a full restoration of the building’s west tower. The east tower has now been fully restored through a National Fund grant of $250,000 and over $500,000 in matching funds raised by Patronato San Xavier.