The island of Sicily is home to a large number of spontaneously mummified remains, dating from the 16th to 19th centuries CE, most of which are located in the renowned Capuchin Catacombs of Palermo, where the oldest mummy is buried (Brother Silvestro da Gubbio, who died in 1599). These remains represent unique evidence of deviant practices within the South of Italy, as the large majority of remains was interred in communal graves, cemeteries, or burials within religious buildings. Only a selection of the local population, mainly formed by members of the aristocracy, middle class citizens, and the clergy, underwent a complex treatment that included dehydration of the corpses, cleaning, and filling of the cavities with either animal or vegetal matter, and eventually clothing and exposure in either a wall niche or a coffin. Since 2007, the Sicily Mummy Project has aimed to scientifically investigate this important biocultural heritage and understand local mummification practices. This study sheds new light on mortuary customs and funeral variability in the region and contextualizes and interprets this treatment of the dead through comparisons with the anthropological and sociological literature.