The focus of past research on substance-abusing adolescents who have a history of physical and/or sexual abuse has been primarily on the prevalence and correlates of abuse. Little research has been conducted among adolescents in substance abuse treatment, particularly in regard to the effects of a prior history of abuse on treatment processes for these youths. This study used data from participants (n=803) in the Drug Abuse Treatment Outcome Studies for Adolescents (DATOS-A), a multi-site prospective treatment outcome study sponsored by the National Institute on Drug Abuse to examine the effects of having a history of physical and/or sexual abuse on treatment processes and post-treatment abstinence. Results were categorized by characteristics of abused and non-abused adolescents, services needed and received, treatment process, and post-treatment abstinence, and predictors of post-treatment abstinence. The findings indicate that abused and non-abused youth in drug treatment programs presented significantly different profiles on treatment entry. Girls had higher rates of sexual abuse and boys had higher rates of physical abuse. A history of abuse was associated with more severe substance use. Abused and non-abused youth did not differ in their rates of post-treatment abstinence. The findings demonstrate that substance-abusing adolescents with a history of physical and/or sexual abuse had more serious problems and greater service needs and that these were complex relationships among gender, type of abuse exposure, treatment processes and post-treatment abstinence. Tables and references