A prospective follow-up study of the progression of HIV infection, from seroconversion to onset of opportunistic infections (OI) indicative of immune deficiency and to death, was performed in a cohort of 54 HIV-1 antibody positive Filipino female commercial sex workers (FCSW). The cumulative probability of having a CD4+T cell count of3and/or an OI indicative of severe immune deficiency was 52.9% within 5 years and 73.8% within 6 years after seroconversion. The cumulative probability of death was 52.1% within 6.5 years following seroconversion and 52.7% within 1.5 years after a depressed (3)CD4+T cell or onset of an OI. Although several OI associated with immune impairment were observed, a CD4+cell count of3was the initial indicator of a failing immune system in more than 50% of the patients.Mycobacterium tuberculosisor unidentified acid fast bacilli (presumed to beM. tuberculosis) andPneumocystis cariniipneumonia were the initial indictors of immune deficiency in the remaining patients.