Although the negative long-term effects of specific childhood risk factors - sexual and physical abuse, parental mental illness and substance abuse, and out-of-home placement - have been recognized, most studies have focused on just one of these risks and have not examined the joint impact of several risk factors. This paper examines the prevalence of these five childhood risk factors among the dually diagnosed (mentally ill and substance abusing) homeless in rehabilitation programs. It further assesses the impact of each of these risk factors individually and in combinations of two on the social functioning skills and rehabilitation progress of these multiply disadvantaged clients. (Authors)