The patron saint of Chiusavecchia is Saint Blaise, celebrated on 3 February together with Saint Francis de Sales, to whom the same parish church in the historic centre is dedicated. The current building derives from a pre-existing complex, and the restoration work was completed at the end of the 17th century; inside it holds a wooden crucifix datable to the 15th or 16th century.
Above the settlement stands the sanctuary of the Madonna dell'Oliveto, built in the course of the 16th century and repeatedly remodelled over time: besides a notable collection of paintings, it holds an 1861 organ, built by the Agati firm and recently restored thanks to the financial contribution of the town's own residents. Among the territory's other religious buildings are the church of the Presentation of the Blessed Virgin Mary in the hamlet of Olivastri, built in the 18th century and home to an 18th-century painting, and the church of Saints Vincent and Anastasius in the hamlet of Sarola, erected in the 17th century with paintings of the period and wooden altars.
