Objective: This study evaluated the relationship between a family adversity index and DSM-IV attention-deficit/hyperactivity disorder (ADHD) subtypes and associated behavior problems. The relationship of family adversity to symptoms and subtypes of ADHD was examined. Method: Parents and 206 children aged 7-13 completed diagnostic interviews and rating scales about socioeconomic status, parental lifetime psychiatric disorders, marital conflict, and stressful life events. Results: Children with ADHD combined type experienced more risk factors than community controls (p = .002) or children with ADHD predominantly inattentive type (p = .02). The families of children with ADHD combined type described more risk factors associated with family adversity than the families of children with ADHD inattentive type and the control group. Parent-rated symptoms of child inattention/disorganization were related uniquely to the adversity index score independently of conduct disorder symptoms. Children's perceptions of marital conflict were independently related to inattention and hyperactivity behaviors as rated by parents and teachers after control of all other risk factors. Oppositional defiant symptoms were independently related to marital conflict and maternal psychopathology, whereas conduct disorder symptoms were uniquely related to low socioeconomic status and maternal psychopathology. Conclusions: Family adversity is related to ADHD combined type in children and may be related specifically to ADHD symptoms in addition to conduct disorder symptoms.