An alcohol misuse prevention study (AMPS) curriculum for fifth- and sixth-grade students was developed, implemented and evaluated with over 5,000 students. The AMPS program emphasized social pressures resistance training, focusing on the immediate effects of alcohol, risks of alcohol misuse and social pressures to misuse alcohol. Schools were randomly assigned to curriculum, curriculum plus booster or control groups with half of each group pretested and all posttested. Measures focused on susceptibility to peer pressure, internal health locus of control, understanding of the curriculum material, alcohol use and alcohol misuse. After 26 months, there was a significant treatment by occasion interaction on internal health locus of control (sixth grade). A significant treatment by occasion interaction effect was also found with respect to curriculum measures in both grades. There was no significant treatment by occasion interactions with respect to alcohol use or misuse when the groups as a whole were considered. When subgroup analyses based on type of prior drinking experience were conducted, however, significant program effects on alcohol misuse were found among sixth-grade students who had experienced unsupervised as well as supervised drinking prior to the prevention program.