Young people who experience homelessness, in Australia and in other western contexts (US, Canada, England), are widely perceived to use and abuse alcohol and drugs. The available research indicates that homeless young people use all drug types, whether injected or otherwise, more frequently than their home-based peers. Debate exists in the research and policy literature about whether drug use is a cause or consequence of homelessness. In a study exploring homeless young peoples reasons for leaving home, we examined the relationship between young people's drug use and their pathways into homelessness. Brief qualitative interviews were conducted with 302 homeless young people (12-20 years). Following a thematic analysis of interview transcripts, four pathways into homelessness involving personal or familial drug use were identified. One-third of the participants indicated that personal or familial drug use was a critical factor in them leaving home. Of these, just over half indicated that personal drug use was a direct or indirect cause of their homelessness and one-quarter indicated that familial drug and alcohol use was the critical factor that led them to leaving home. One-quarter indicated that their drug use only began after they became homeless. Family conflict, if not family breakdown, was implicated in all four pathways out of home.