The term social exclusion refers to not only the phenomenon of unemployment and marginalization but the development of a population removed from economic progress and the distribution of wealth. Within the scope of social exclusion, illicit drug users form a priority group for enrollment for HIV/AIDS care and prevention programs. Illicit drug use in a framework of marginality accelerates the exclusion process, making reversal very difficult in some cases. This study attempted to describe the social exclusion experienced by cocaine and heroin users, as well as their habits in drug abuse and pinpoint certain indicators among people who continue to inject illicit drugs. The study centered on drug users in two Andalusian cities, Granada and Seville in the year 2000. The sample consisted of 391 heroin or cocaine users. A structured, face-to-face interview lasting approximately 1 hour was administered. Health and social indicators show a high incidence of self-reported infectious diseases, poor mental health, criminality, and early onset of heroin and cocaine use. Having an intimate partner who injects, having been in prison, and homelessness all tended to increase the probability of injecting. The study shed light on the situation of social exclusion experienced by a sample of men and women addicted to heroin and cocaine. Tables and references