This article: concerns the social origins and characteristics of the organisation of drug trafficking at the retail level in the city of Rio de Janeiro. It analyses one of its consequences: violence, which has lain at the heart of the high homicide rates and rates of crimes of violence in this former capital of Brazil for the last three decades. Organised as gangs in the favelas, and in other residential areas of high deprivation, drug traffickers have started to create kinds of local “no-go areas” and to establish links with the residents of each of these areas. The article suggests analysis of the forms these links take and of the kinds of power relation involved, which change each year, depending upon the extent of enforcement by the authorities, police corruption and the occurrence of militias which “offer protection” to residents against the traffickers, but through extortion and violence.