This paper, based on ethnographic research, outlines the relationships between the formal economy and the illicit drugs economy in three Italian cities. The authors argue that the economy of illicit drugs is extremely flexible, as it is capable of adapting to the legal economy in diverse contexts. They examine the way in which the heroin business intermingles with legal business in Naples, where the features of a so-called hidden economy prevail. They also analyse how the economy of illict drugs has entered areas, like Verona, characterized by the presence of healthy, competitive, mid-range industries. Here, the absence of traditional organized crime is compensated for by efficient licit firms. Finally, they describe how the heroin economy has found ways of penetrating the context of Turin, which is typified by the prevalence of monopolistic firms. The connections unravelled in the present paper, albeit in a tentative manner, are worth considering as pointers to new theoretical and empirical knowledge about heroin use.