Kidskin was a sun-protection intervention study involving 1776 children attending 33 primary schools in Perth, Western Australia. There were three study groups: a control group, a moderate intervention group and a high intervention group. In addition to receiving a specially designed curricular intervention (1995-1998), the moderate and high intervention groups received an environmental intervention aimed at creating SunSmart schools (1996-1998). The environmental intervention focused on encouraging implementation of "No hat, no play" policies and reducing sun exposure at lunchtime. In 1995 and 1998, observational methods were used to measure children's lunchtime sun exposure (i.e. polysulfone film badges) and hat wearing (i.e. video-taping of children). The proportion of children wearing broad-brimmed hats or legionnaire caps increased in seven of the eight high intervention schools between 1995 and 1998. In three schools, however, the impact was very positive with almost all children wearing these hats in 1998. There was no improvement in wearing these types of hats in either the moderate intervention group or the control group. In terms of sun exposure, there were only small non-significant differences among the three groups in terms of lunchtime sun exposure. The Kidskin program had a positive effect on hat wearing in the playground, but did not change children's use of shade at lunchtime. In this study, disseminating policy guidelines to schools using a mail-only strategy was ineffective, even when combined with an awards program. More information on "champions" who bring about change in schools is required. (Contains 5 tables and 1 figure.)