The church of San Paolo della Croce is a sacred building located in Porto Ercole, in the municipality of Monte Argentario.
Built in 1966, it houses an important 16th century painting depicting Saint John the Baptist in the desert, donated in 1957 to the parish of Porto Ercole by the Cornaggia Medici family Castiglioni in memory of his son. The work, previously attributed to Girolamo da Carpi, was recently ascribed to the Lombard painter Lorenzo Leonbruno.