The Immaculate Conception Parish Church is the oldest Roman Catholic church in Los Baños, its current stone structure dating from the 18th century though the parish itself was established much earlier by the Spanish Augustinians. The church faces the town plaza in the standard Spanish colonial urban layout — church, plaza, municipal hall arranged on the same axis.
The interior preserves several old devotional images and the painted ceiling is typical of provincial Laguna Catholic church decoration. The church is still in active use for daily and Sunday masses. It is the architectural and spiritual centre of the older part of town and worth a brief stop as part of a walk through the original poblacion.