The aim of this pilot study was to evaluate the efficacy of a new school-based eating disorder prevention program designed to reduce dietary restraint and the level of preoccupation with regard to shape and weight. One hundred and six (61 females and 45 males) 11 to 12-year-old students were evaluated, 55 of whom participated in the program (experimental group). An additional 51 students formed the control group. The program met for six sessions, two hours per session. After six months, the experimental group received two booster sessions of two hours in two consecutive weeks. Outcome measures included the Eating Disorder Examination Questionnaire (EDE-Q), the children’s version of the Eating Attitudes Test (EAT), the Rosenberg Self-Esteem Scale (RSES), and a Knowledge Questionnaire (KQ) devised by the authors of the program. The questionnaires were administered in both the experimental and control groups, one week before the intervention, one week afterwards, and at six-month and 12-month follow-ups. Unlike a previous school-based eating disorder prevention program, in the experimental group both an increase in knowledge and a decrease in some attitudes were maintained at 12-month follow-up (Eating Concerns EDE-Q scores). Although more intensive interventions seem necessary to modify shape and weight concern and self-esteem, these findings suggest that the intervention had been useful since it led to both an increase in knowledge and a decrease in some dysfunctional eating attitudes.