Despite the broad recognition in social work that services are more effective when they are tailored to individual client needs, we have only limited evidence of the impact that services matched to client needs have on treatment outcomes. This study examines gender differences in the impact of matched services, access services, and outcome-targeted services on substance abuse treatment outcomes by using data collected from 1992 through 1997 for the National Treatment Improvement Evaluation Study, a prospective, cohort study of substance abuse treatment programs and clients. The analytic sample consists of 3,027 clients (1,105 women and 1,922 men) who reported needed services from 59 treatment facilities. Findings from the study indicate that overall programs have only limited success in targeting services to client needs, but when they do, receipt of substance abuse counseling and matched services predicts both remaining in treatment and reduced posttreatment substance use for both women and men, but especially for women.