To investigate the incidence and patterns of acute anterior uveitis (AAU) in Central Australia and specifically to study the relative frequency of AAU in Australian Aborigines compared with that in non-Aboriginal patients. Prospective, observational study of all patients seen by the Central Australian Ophthalmology service over an 8-month period. The incidence rate of AAU in Central Australia was 35.9 cases/100,000 population per year. Forty-two per cent of the 1955 patients seen during the study period were Australian Aboriginal patients; however, all but one patient with AAU were Caucasian. The difference in the incidence of AAU between the Indigenous and non-Indigenous populations was statistically significant (p = 0.03, Fisher's exact test). Four of the nine Caucasian patients with AAU were HLA-B27-positive. The single case of AAU in an Australian Aborigine was a recurrent episode of HLA-B27-positive AAU. A family history of this patient revealed that both her grandfathers were Caucasian. The incidence and pattern of AAU in Central Australia is comparable with that in other geographical regions. However, AAU occurs very infrequently in Australian Aborigines compared with that in the non-Indigenous population of Central Australia, further implicating the importance of genetic factors in the pathogenesis of AAU.