Mortality rates from heart disease and stroke in Australia have been falling for more than 20 years. No completely satisfactory explanations for this trend exist. However, it is believed to be due, at least in part, to changes in the incidence of cardiovascular disease arising from changes in the prevalence and severity of risk factors for cardiovascular disease. The adult community of Busselton in Western Australia participated in cross-sectional health surveys every three years from 1966 to 1981. This paper describes secular trends from 1966 to 1981 and age trends from 25 to 80 years for cardiovascular risk factors in Busselton men and women. Downwards secular trends were observed for mean blood pressure and smoking for men and women, upwards trends were observed for body mass index in men, and mean cholesterol was approximately constant over this period. The age and secular trends were consistent with other Australian studies conducted in the 1980s and with overseas studies. An estimated 67 per cent of the decline in cardiovascular mortality rates among Busselton men and 22 per cent of the decline among Busselton women may be attributed to changes in the prevalence of risk factors for cardiovascular disease.