Using data from the annual surveys of individuals receiving HIV related treatment or other care from 1996 to 2000, trends in prevalent numbers of diagnosed HIV infections have been extrapolated to the years 2001-05. Results show that the adjusted prevalent number for 1996 was 14,205 and that this has increased by 62% by the end of 2000, and will have increased by 139% by the end of 2005. The drivers for this increase have been the sustained rise in diagnoses in infections heterosexually acquired in sub-Saharan Africa and the continuing numbers of new diagnoses in men who have sex with men.