While much of the research literature recognizes the role mental illness may play in maltreatment, few studies have assessed formal psychiatric diagnoses among maltreating parents. The current study identifies and describes the types of DMS-II-R and IV mental health diagnoses in maltreating caregivers and also assesses the characteristics of mental illness in their maltreated children. Psychiatric diagnoses were obtained from 53 maltreating families, including at least 1 primary caregiver and 1 maltreated child, and for a control group of 46 nonmaltreating families, including at least 1 caregiver and 1 child. Child and adolescent participants completed the Children’s Global Assessment Scale (CGAS). Child and adolescent participants were also evaluated using a detailed trauma interview. Results of statistical analyses indicated that maltreating mothers demonstrated a significantly higher lifetime incidence of anxiety disorders, mood disorders (72 percent), alcohol and/or substance abuse, suicide attempts, and comorbidity of two or more psychiatric disorders than the control mothers. Male maltreating caregivers had a significantly high incidence of lifetime alcohol and/or substance abuse than their nonmaltreating counterparts. A full 94 percent of maltreated children and adolescents reported anxiety disorders while another 89 percent exhibited mood disorders and 72 percent displayed disruptive disorders. Clinically significant symptoms of posttraumatic stress disorder were present in 85 percent of child and adolescent participants. Seventy-two percent of maltreated children suffered from comorbidity involving both emotional and behavioral disorders. The findings indicate that, overall, families involved in maltreatment suffer histories of psychiatric comorbidity. Policies designed to break the intergenerational transmission of maltreatment should focus on identifying and treating psychiatric comorbidity in these families. Tables, references