The patroness of Sant'Agata Fossili is Saint Agatha, celebrated on 5 February, after whom the parish church is named.
The church was completely restored and decorated in 1905-1906 by Gambini and its façade was radically altered in 1921; the municipality of 441 inhabitants in the province of Alessandria also holds the Chiesa di San Michele and two oratories, of the Immacolata and of Saints Rocco and Sebastiano.
