Decreasing the number of homeless drug users is one of the main characteristics of inner city drugs policy. The present study selected an urban-ethnographic perspective (the subculture theory) in order to explore why one drug user is homeless and another 7 not, and to attempt to describe and define the homeless and their immediate social environment. These issues were formulated into the following research questions: 1. What are the sociodemographic characteristics of homeless drug users in Rotterdam, and do they differ from domiciled drug users? 2. What are their living conditions? 3. What are the reasons for being homeless? 4. Does the period of homelessness play a role in the need to change one's lifestyle? Five research methods were employed for this study: a literature search, interviews with key persons, field notes from community fieldworkers, a survey among drug users (n = 204), and photographic reports from six homeless users. Data were collected in 1998/1999. The results document that in our study population there were more women, more illegal persons, and more foreigners than among domiciled drug users, and that the homeless group used heroin and cocaine on more days. A large proportion of the homeless users had no identity papers and no health insurance. This did not, however, lead to more self-reported sickness or a higher prevalence of infectious diseases compared with nonhomeless drug users. Easily accessible (low threshold) social care centers and assistance are very important. Few of the homeless had voluntarily chosen a homeless life-most describe an event that was a trigger for their homelessness. The average duration of being homeless was 17 months, and the longer someone had been homeless the less inclined they were to change their situation. This paper also discusses policymaking implications.