The ultraviolet (UV) index provides an opportunity to warn people about the degree of hazard that exists on a particular day and subsequently lead to the adoption of sun protective behaviors. While the UV index has been promoted in Australia for some time, little research has been conducted into the understanding and use of the index. As such, a random telephone survey of 501 adults was conducted in December 1999 to gather data into the public's understanding and use of the UV index in Perth, Australia. A high awareness of the UV index existed among the respondents, with 90% indicating they had heard of the term UV index. However, only 5% indicated they had noticed the UV index/forecast for that particular day. The results indicate that a campaign to increase awareness of the UV index by the public is not warranted, but that efforts should be focused on developing tools to communicate behavior change messages linked to the UV index levels. The research was conducted with funding from Healthway, Health Promotion Foundation of Western Australia.