This study examined the prevalence of a history of various combinations of childhood maltreatment types (physical abuse, sexual abuse, and witnessing of maternal battering) among adult members of a health maintenance organization (HMO) and explored the relationship with adult mental health of the combinations of types of childhood maltreatment and emotional abuse in the childhood family environment. A total of 8,667 adult members of an HMO completed measures of childhood exposure to family dysfunction, which included items on physical and sexual abuse, witnessing of maternal battering, and emotional abuse in the childhood family environment. The adults' current mental health was assessed by using the mental health scale of the Medical Outcomes Study 36-item Short-Form Health Survey. The prevalences of sexual abuse, physical abuse, and witnessing of maternal violence were 21.6%, 20.6%, and 14.0%, respectively, when the maltreatment types were considered separately. Among respondents reporting any of the maltreatment types, 34.6% reported more than one type of maltreatment. Lower mean mental health scores were associated with higher numbers of abuse categories (mean=78.5, 75.5, 72.8, and 69.9 for respondents with no, one, two, and three abuse types, respectively). Both an emotionally abusive family environment and the interaction of an emotionally abusive family environment with the various maltreatment types had a significant effect on mental health scores. Childhood physical and sexual abuse, as well as witnessing of maternal battering, were common among the adult members of an HMO in this study. Among those reporting any maltreatment, more than one-third had experienced more than one type of maltreatment. A dose-response relation was found between the number of types of maltreatment reported and mental health scores. In addition, an emotionally abusive family environment accentuated the decrements in mental health scores. Future research examining the effects of childhood maltreatment on adult mental health should include assessments of a wide range of abusive experiences, as well as the family atmosphere in which they occur.