The incidence of skin cancer is increasing worldwide, and Spain is no exception. SolSano is the first Spanish health education program for sun safety directed at elementary school children. The objective was to evaluate SolSano's effects on students' knowledge, attitudes and practices about sun safety. A non-randomized, before/after, community intervention without control group, with schools as the unit of intervention, was used for the study. Five thousand eight hundred and forty-five children from 215 Aragonese Primary Schools (Grades 1-2) participated in the program in their classes during the 2004-2005 academic year. The educational package contained an activity guide for teachers, a workbook for each pupil, a poster and an informative pamphlet for families. The pre-test and post-test surveys were similar and were composed of two parts: the first part uses the 'Draw and Write research strategy' and the second part was a questionnaire. One thousand five hundred and twenty-two students completed both questionnaires, 49.2% were boys, and the mean age was 6.6; 45.7% self-reported pale skin and easy sunburn and 48% dark skin and rarely sunburn; 72.3% of the children reported having dark hair and eyes, and 51.6% freckles or moles. The mean score for the complete survey significantly increased by 1.55 points (1.38-1.72) after the intervention (p < 0.001), and girls did better than boys. Sunscreens were the most-commonly employed sun protection strategy while strategies such as seeking shadow and wearing clothes exhibited the greatest increase after the SolSano program [percentage increase of 19.3% (16.4-22.3) and 26.8% (23.4-30.3), respectively]. At baseline, 35.8% of children reported sunburns during the previous summer compared with 23.5% after the program. SolSano also achieved a slight reduction in the percentage of students who desired to be tanned. Our study demonstrates that significant knowledge can be acquired, attitudes regarding the healthiness of a tan can be modified and intentions to change sun protection behaviour can be promoted by well-designed educational programs.