This study compares the clinical characteristics of and treatment implications for five demographic groups of addicts: Black and White males and females and Hispanic males evaluated in Spanish. Among the 522 addicts, the 60 Puerto Rican males had the most frequent unemployment, the least education, the most polydrug abuse and violent crimes, the highest rate of schizophrenic or anxiety disorders, and more neurotic and depressive symptoms than the other male addicts. These addicts seem to have the greatest liabilities of any group and may need residential treatment. The 126 female addicts had frequent unemployment, high rates of depression and anxiety disorders, and more severe medical problems than men. This suggested that they have some treatment needs that are different than those of male addicts, including care for dependent children. Some differences between Black and White males in drug use were also found between Black and White females. White males (177) had a high rate of antisocial personality and polydrug abuse but had fairly good economic functioning. A structured treatment program to deal with their common illicit activities may be necessary for these addicts. The 159 Black males had poor occupational functioning but relatively little psychopathology. Vocational rehabilitation may be needed for them.