Injection drug users are at high risk for homelessness and human immunodeficiency virus (HIV) infection. This study sought to examine incidence rates and the social and economic antecedents of homelessness of impoverished inner-city injection drug users. Of the 569 participants, from a nontreatment sample who participated HIV prevention study, interviewed at baseline, 324 (57%) were reinterviewed 5.2 months later. At baseline 48% of the participants reported that they had been homeless in the past 10 years. Of the 324, 18% reported that at both interviews they had been homeless within the prior 6 months, 12% reported homelessness at baseline but not at follow-up, and 8% reported homelessness at follow-up but not at baseline. At baseline personal social support network characteristic of size of material aid and size of sex network was found to be associated with self-reports of homelessness. Baseline reports of presence of mother in personal network, size of material aid network, and network density were found to be associated with reports of homelessness at follow-up. These result suggest the need for alternative approaches to addressing issues of homelessness injection drug users.