Objectives: To determine what proportion of employees at the largest private-sector companies in South Africa have access to HIV/AIDS care and treatment, including antiretroviral therapy (ART); how many employees are enrolled in disease management programmes; how many are receiving ART; and which approach to the financing and delivery of care is proving most successful at reaching eligible employees. Design: All 64 private-sector and parastatal companies with more than 6000 employees in South Africa were identified and contacted. Those that agreed to participate were interviewed by telephone using a structured questionnaire. Results: Fifty-two companies agreed to participate. Among these companies, 63% of employees had access to employer-sponsored care and treatment for HIV/AIDS. However, access varied widely by sector. Approximately 27% of suspected HIV-positive employees were enrolled in disease management programmes, or 4.4% of the workforce overall. Fewer than 4000 employees in the entire sample were receiving ART. In-house (employer) disease management programmes and independent disease management programmes achieved higher uptake of services than did medical aid schemes. Conclusions: Publicity by large employers about their treatment programmes should be interpreted cautiously. While there is a high level of access to treatment, uptake of services is low and only a small fraction of employees medically eligible for ART are receiving it.