This article presents the activities of the Papal Customs Service in the 19th century. This service consisted of civil officials and a military corps known as Truppa di Finanza (Finance Troop), was established in 1786 by Card. Ruffo, the Papal States’ Treasurer General, to combat rampant smuggling. The main customs posts of the Papal States were located in the free ports of Ancona and Civitavecchia, in the city of Ferrara and in Rome. It should be noted that customs regulations were not uniform throughout the country. The practice of smuggling inflicted significant harm upon the Papal States, which had adopted a protectionist stance, entailing the imposition of taxes on foreign goods to promote domestic production. A special procedure was adopted to facilitate the discovery of cases of smuggling or corruption.