The patron saint of Diano Arentino is Saint Margaret of Antioch, celebrated on 20 July, in the parish church dedicated to her in the main town, first officially mentioned on 23 April 1469. Inside are preserved a 1602 painting, by an unknown artist, depicting the Madonna del Rosario with the twelve Stations of the Cross, and a polyptych depicting Saint Margaret and Saint Antoninus, perhaps originally from a 16th-century chapel.
The town also preserves the parish church of San Michele Arcangelo, in the hamlet of Diano Borello, and that of San Bernardo, which today houses a painting depicting the Sacred Heart of Mary, Saint Martin and Saint Isidore, originally placed elsewhere.
