This study reports on the effects of having a history of childhood sexual abuse (CSA) on treatment outcomes among substance abusing men and women (N = 2,434) in a national, multisite study of drug treatment outcomes. A history of CSA was reported by 27.2% of the women and 9.2% of the men. Controlling for gender, compared to patients without CSA, patients reporting CSA were younger at entry into the current drug treatment, were more likely to be White, were more likely to have a comorbid mental disorder, be alcohol or cocaine dependent, had higher levels of criminal activities, had a higher level of problem recognition, and had a more negative peer influence. Controlling for these correlates, a history of abuse was related to a lower likelihood of posttreatment abstinence. (Contains 2 tables and 1 figure.)