This study examined the impact of physical and sexual trauma on a sample of 239 homeless men. Study participants completed a self-administered survey that collected data on demographics, exposure to psychological trauma, physical health and mental health problems, and substance use or misuse. Binomial logistic regression analyses were used to examine the relative significance of demographic factors and the four types of trauma exposure associated with three outcomes: mental health, substance abuse, and physical health problems. The authors found that trauma history was significantly associated with more mental health problems but was not associated with substance abuse problems for homeless men. This study reinforces service providers' perceptions that because many homeless men experience the long-term, deleterious effects of not only current stressors, but also abuse and victimization that often begin in childhood, homeless men are a subpopulation in need of proactive prevention services that emphasize long-term continuity of care rather than sporadic crisis-based services. Study findings suggest that mentally ill, homeless men need proactive services that address the sequelae of abuse with care that is specialized and distinctly different from care for homeless adults with substance abuse or physical health care issues.