Objective: To evaluate psychiatric disorders and impairment in school-age and adolescent children of opiate-dependent patients. Method: One hundred fourteen children, aged 6 to 17 years, of 69 white methadone maintenance patients with (n = 30) and without (n = 39) major depression were evaluated for DSM-III-R diagnoses by the Schedule for Affective Disorders and Schizophrenia for School-Age Children-Epidemiologic version and best estimate, and by measures of functioning (Children's Global Assessment Scale. Social Adjustment Inventory for Children and Adolescents, WISC, Peabody Picture Vocabulary Test), and compared with children of historical controls without substance abuse history. Results: Sons of opiate addicts with major depression were at increased risk for conduct disorder and global, social, and intellectual impairment compared with sons of opiate addicts without major depression and/or sons of controls with neither drug dependence nor depression Sons of opiate addicts without major depression differed little from controls. Daughters of opiate addicts did not differ from controls in rates of disorders but had poorer social adjustment and nonverbal intelligence. Conclusions: Children of opiate-dependent patients, particularly sons of addicts with depression, may be at risk for a developmental path toward antisocial personality and poor social and intellectual functioning. Treatment settings such as methadone maintenance might afford an opportunity for primary and secondary prevention, both through early detection of childhood disorders and treatment of parental drug dependence and psychopathology.