"Kidskin" was a 5-year (1995-1999), school-based intervention trial among first-grade children in Perth, Western Australia. It aimed to assess whether a sun-protection intervention could protect against nevus development on the trunk, face, and arms. Included were a control group, a "moderate intervention" group, and a "high intervention" group. Control schools taught the standard health curriculum, while intervention schools received a specially designed sun-protection curriculum over 4 years. The high intervention group also received program materials over summer vacations when sun exposure was likely to be highest and were offered low-cost sun-protective swimwear. After adjustment for baseline nevus counts and potential confounding, nevus counts on all body sites were slightly lower in both intervention groups relative to the control group at follow-up, although the differences were not statistically significant and the high intervention was no more protective. Children in the moderate and high intervention groups, respectively, had fewer nevi on the back (6%, 95% confidence interval (CI): 0, 12; 4%, 95% CI: -3, 11), chest (boys) (5%, 95% CI: -4, 13; 3%, 95% CI: -8, 14), face (11%, 95% CI: 0, 21; 9%, 95% CI: -6, 21), and arms (8%, 95% CI: -1, 17; 3%, 95% CI: -10, 14).