Of 1947 Aboriginal women who resided in non-metropolitan regions of Western Australia and gave birth during January 1983 to February 1985, 42% of women were screened prenatally for the presence of hepatitis B surface antigen (HBsAg). The proportions of Aboriginal women who were screened varied from 17% in the southern divisions to 72% in the Kimberley region. The screening programme identified 29 Aboriginal women with a positive result of the test. On this basis, the estimated prevalence of HBsAg among non-metropolitan Aboriginal women was 3.6% (95% confidence interval, 2.5%-5.1%). According to the geographical location of the mother's residence, the observed prevalence of HBsAg varied from 0 in the southern divisions to around 4%-5% in the central and eastern divisions.