BACKGROUND: In sub-Saharan Africa, data for short-term risk of AIDS or death, which might inform decisions about when to start antiretroviral therapy (ART), are scarce. Our aim was to investigate these risks in patients who had no access to ART or who were given zidovudine alone. METHODS: 6-month risks (%) of death, AIDS, and combined risk of AIDS and death (AIDS/death) were calculated according to CD4-cell count category of less than 200 cells per microL, 200-350 cells per microL, or greater than 350 cells per microL, stratified by WHO clinical stages 1 and 2 combined, 3, or 4 in untreated patients (n=1399) seeking care in tertiary public-sector HIV clinics before widespread availability of ART in Cape Town, South Africa. FINDINGS: Risk of death for WHO stages 1 and 2 was 3.5% for those with less than 200 cells per microL, 2.8% for 200-350 cells per microL, and 1.2% for greater than 350 cells per microL. The corresponding rates for WHO stage 3 were 10.8%, 4.3%, and 4.9% and for stage 4, 22.2%, 10.3%, and 13.8%. 52% (90) of deaths took place in patients without AIDS. 6-month risk of AIDS for WHO stages 1 and 2 was 3.5% for those with less than 200 cells per microL, 1.6% for 200-350 cells per microL, and zero for greater than 350 cells per microL. The corresponding rates for those with WHO stage 3 disease were 17.4%, 7.0%, and 2.2%. INTERPRETATION: In this study, risk of AIDS in patients with a CD4-cell count of less than 200 cells per microL or greater than 350 cells per microL was similar to that previously reported from European cohorts, but was 1.9 times greater for those with CD4-cell counts of between 200 and 350 cells per microL. The high death rate before development of AIDS and a high risk of AIDS in those with CD4-cell counts of 200-350 cells per microL indicate that delay in initiation of ART is associated with increased morbidity and mortality. These findings might help to amend criteria for start of ART in resource-limited settings.