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. This article examines the prevalence of these five childhood risk factors among dually diagnosed (mental illness and substance abusing) homeless adults in rehabilitation programs. It further assesses the impact of each risk factor individually and in combinations of two on the social functioning skills and rehabilitation progress of these multiply disadvantaged clients.