This study examined the relationship between childhood maltreatment and injection drug use initiation among high risk youth. The authors used data from the At Risk Youth Study, a prospective cohort study of street-involved youth in Vancouver. All participants were street youth between the ages of 14 and 26 that had recently used illicit drugs other than marijuana. The 560 participants completed an interviewer-administered questionnaire and the Childhood Trauma Questionnaire. A multivariate logistic regression model revealed factors that were independently associated with initiating injection drug use. Physical abuse was independently associated with having initiated injection drug use after adjusting for a variety of socio-demographic and psycho-social variables, and other forms of maltreatment. The authors posit that physical abuse may impact the coping skills of youth, such that these youth are unable to deal with the high-risk situations that often confront street-involved individuals. This lack of coping skills may result in a greater vulnerability to injection drug use. Having a parent who used illicit drugs was associated with a lower likelihood of having initiated injection drug use. The authors suggest that these youth witnessed the negative outcomes associated with injection drug use through their parents, and thus were less likely to have used injection drugs themselves.