The Mississippi Alcohol Safety Education Program (MASEP) is a court-mandated driving under the influence (DUI) intervention for persons convicted of DUI. This study describes the evolution of the curriculum, evaluates the effectiveness of MASEP in reducing recidivism, and examines whether recent program revisions have led to improvements in reducing recidivism. Findings indicate that between 2005 and 2009 individuals who completed MASEP had significantly lower recidivism rates at 12-months follow-up compared to those who did not complete or did not enroll in MASEP, and that the most recent curriculum is more effective in reducing recidivism than its predecessor. (Contains 3 tables.)