Project SUCCESS (PS) is a substance use prevention program that targets indicated high school students. We used archival data to explore the program's effects on students' academic achievement and disciplinary problems. It is essential to demonstrate such effects, if prevention curricula are to survive in schools that face multiple competing demands for class time. Using a quasi-experimental design that compared students exposed to the program to those not exposed in five schools, we examined the effects of PS on grades, absenteeism, and disciplinary problems. Using longitudinal analyses that linked individual students' program exposure data to their academic performance, we found that PS had a positive impact on both grades and absenteeism for two years following exposure. We note that these findings are particularly fortuitous, as PS was not designed to affect these outcomes. We recommend that future evaluations of school-based prevention curricula routinely include academic performance. (Contains 5 tables and 1 figure.)