The assessment by Lester Venter (Apr 2, p 1215) of the extent to which the private sector is filling the need for antiretroviral treatment (ART) for HIV/AIDS is misleading. Public announcements by a few large private companies about the scale of their HIV/AIDS programmes should be interpreted cautiously. Few companies have made public what proportion of employees are eligible for the programmes, what proportion are in need of treatment, or how many are actually receiving it. We recently surveyed the experience of large companies in South Africa in making ART available for employees. In interviews with 52 of the 64 private-sector employers with more than 6000 permanent employees, we found that 80% of the 95 000 employees at these companies have access to ART. Among the 25 companies with knowledge of uptake rates, however, only 3·5% of all employees are being managed for HIV/AIDS. About 0·5% of the total and 14·4% of those being managed are currently receiving ART. The prevalence of HIV among employees at the 27 companies that have made and disclosed estimates was 16·1%, suggesting that about a fifth of those with HIV are aware of their own status and agreed to seek care.