Abstract
Worldwide, the human immunodeficiency virus exhibits a great genetic variability, with multiple circulating subtypes of the virus. This variability allows study of the movement of HIV strains within and between human populations but also has implications for diagnosis, treatment and monitoring. The type of HIV causing the epidemic in Australia is changing from being homogeneous subtype B, reflecting a greater regional diversity. In this paper the classification of HIV-1 subtypes and their distribution within the Australasian region are reviewed and the implications of these distribution patterns discussed.