To estimate the proportion of outpatient visits that could be managed at a primary-care level, by World Health Organization (WHO) clinical staging. Prospective, descriptive study. Six medical doctors in a tertiary hospital HIV ambulatory clinic recorded clinical diagnoses, WHO clinical staging and their recommendation regarding the appropriate level of care for each outpatient seen. All HIV-infected patients attending a public-sector, urban, South African, referral and teaching hospital HIV outpatient clinic between September and November 1992. There were 238 visits by 148 patients during the study period. Of 238 visits, 165 (69.3%) were deemed suitable for treatment at the primary-care level. After allowing for contradictory responses, at least 141 visits (59.2%) could be appropriately treated at the primary-care level. Although all six doctors assessed more than half of their visits as suitable for primary care, there were significant differences among them. In total, 83 visits (34.8%) needed a medical specialist, and 45 (18.9%) required tertiary-care facilities. Of all the visits, 58 (24.9%), 51 (21.9%), 60 (25.8%) and 64 (27.4%) were classified as WHO stages 1, 2, 3 and 4, respectively. For these stages, 55 (94.8%), 38 (74.5%), 42 (70.0%) and 26 (40.5%) visits, respectively, were suitable for treatment at a primary-care facility. Many of the outpatient visits to this outpatient specialist clinic could have been safely cared for at a primary-care level. As the severity of the disease increases, there is a decrease in the proportion of patients that can be treated at a primary-care level.