OBJECTIVE Prior research on patients with substance use disorders has shown that lifetime physical or sexual abuse is associated with more impaired functioning at treatment intake. The present study sought to determine whether physical or sexual abuse also predicted treatment response (posttreatment outcomes) of individuals with substance use disorders. METHODS Male (n = 19,989) and female (n = 622) veterans with substance use disorders were assessed with the Addiction Severity Index (ASI) early in treatment and reassessed an average of 12 months later. Treatment outcomes were compared for patients who did and did not report prior physical or sexual abuse in the initial ASI interview. RESULTS Lifetime physical or sexual abuse predicted worse outcomes in six of seven domains of functioning, after controlling for baseline functioning, psychiatric diagnoses and demographic variables. Although women were more likely than men to report being abused, the effect of abuse on treatment outcomes was similar for both genders. Psychiatric problems at baseline mediated the effect of abuse history on outcomes. Abuse history moderated the effect of treatment intensity (contacts per month) on outcomes: More frequent treatment contacts were more beneficial for abused patients than for nonabused patients. CONCLUSIONS Individuals with substance use disorders who have a history of physical or sexual abuse may have higher risk for problematic treatment outcomes as a result of greater psychiatric problems, deficits in social support and possible difficulties in establishing treatment alliance. Clinicians may consider increasing the duration and intensity of treatment to temper the negative effects of abuse on later functioning.