A history of sunburns in early life nearly doubles the risk of developing malignant melanoma in adulthood. From 2001 to 2004, we conducted a cluster-randomized trial of an educational intervention to reduce sunburn rates (primary outcome) and improve sun-protection behavior (secondary outcome) in schoolchildren. A total of 122 Italian primary schools (grades 2 and 3) were randomized to receive, or not, an intervention consisting of an educational curriculum at school, conducted by trained teachers, which included the projection of a short video and the distribution of booklets to children and their parents. Behavior while in the sun was assessed at baseline and 14-16 months after baseline. In a subgroup (44% of the total sample), melanocytic nevi were also counted. Of the 11,230 children enrolled, 8,611 completed the study. A total of 1,547 children (14%) reported a history of sunburns at baseline. At follow-up, no difference in sunburn episodes was documented between the study groups (odds ratio 0.97, 95% confidence interval 0.84-1.13) and similar sun-protection habits were reported. No significant impact of the proposed educational program was documented at 1-year follow-up. Innovative strategies need to be developed to increase the effectiveness of future educational interventions in this area.