What are the conditions conducive to long-term transplantation of mafia groups in new territories? This paper systematically reviews a number of factors that facilitate such an outcome, including: migration from territories with high mafia density; the policy of forcing criminals to resettle outside their region of origin; the existence of mafia wars; two different systems of recruitment into mafia families (merit- and kin-based recruitment); the level of interpersonal trust in the new territory; and the demand for criminal protection. The paper then explores two attempts at transplantation by members of the Calabria-based mafia group `Ndrangheta to the town of Bardonecchia (Piedmont region) and to Verona (Veneto region). While the former case was successful, the latter failed. The paper concludes that features of the local economy – the presence of significant sectors of the economy unprotected by the state and a local rather than export orientation – generate a demand for criminal protection, especially protection against competition, and a demand for services of dispute settlement. Successful transplantation occurs in the presence of such a demand. Generalized migration or forced resettlement of mafiosi are not sufficient to predict transplantation. The paper shows that a high level of interpersonal trust among local law-abiding residents is not sufficient to hinder mafia transplantation, contrary to established theories of social capital and trust.