With rising rates of skin cancer in Australia, there is a need to examine strategies to reduce sun exposure among children. This study aimed to determine the effectiveness of a multifaceted dissemination strategy compared with a simple mail-out strategy in promoting the adoption of comprehensive SunSmart skin protection policies and practices in primary and secondary schools in New South Wales. It also aimed to examine characteristics of the primary and secondary schools that adopted a comprehensive SunSmart policy before and after the intervention. Four hundred randomly selected primary schools and all 381 high schools in New South Wales were randomised to one of two intervention groups. Pretest and post-test surveys of principals were undertaken in 1991 and 1992. Intervention 1 was a simple mail-out of a sample sun-protection policy kit. Intervention 2 comprised the mail-out of the policy kit and a follow-up mail-out of a staff development module. There was a strong intervention effect on adoption of a comprehensive sun-protection policy in primary schools (21 per cent for the 'mail' group compared with 44 per cent for 'mail and staff support' group) but not in high schools (6 per cent and 11 per cent). There was little relationship between adoption of a comprehensive sun-protection policy and sun-protection practices in primary or secondary schools. Further research is needed to determine the most effective ways of ensuring that adoption of a comprehensive sun-protection policy results in effective implementation of sun-protection practices in schools.