This review describes patterns of mortality among adults infected with HIV in the UK and assesses the contributions of late diagnosis of HIV infection and non-HIV-related disease to such mortality. In total, 387 adults with HIV who died between 1 October 2004 and 30 September 2005 after receiving care at 90 clinical centres in the UK were reviewed. Causes of death and scenarios accounting for death were measured. Of the 387 deaths, 218 (56.3%) were readily attributable to infection with HIV. Only 123 (31.8%) deaths were considered not directly related to HIV. Late diagnosis of HIV accounted for 24.0% of all deaths and 35.2% of HIV-related deaths. Infection with HIV remains the main cause of mortality among infected patients in the era of highly active antiretroviral therapy. Late diagnosis of infection with HIV may be the largest potentially remediable factor for HIV-associated death.