Based on judicial files, data on local criminal associations, and interviews with different categories of privileged witnesses, this article focuses on the city of Gela, in southeastern Sicily, an area apparently immune since the late 1970s to the presence of Mafia organizations. Referring to major literature on organized crime, the first part underlies factors contributing to the creation and establishment of Mafia criminal groups in the city. The second specifically considers the characteristics of local organized crime and its system of infiltrating the social and economic fabric, through violence and intimidation. The last section deals with recent positive signs of opposition to the Mafia by local institutions and civil society, which could also lead to more than merely judicial methods for fighting criminal associations. (Published Abstract)