The Perinatal HIV Research Unit (PHRU) recently established an HIV AIDS Vaccine Division (HAVD) in order to test multiple phase I/II HIV vaccine candidates as safely and as quickly as possible, in strict adherence to the International Conference on the Harmonization of Good Clinical Practice (ICH GCP) and the South African Department of Health GCP guidelines. The purpose of testing multiple phase I/II candidates is to quickly identify the most suitable vaccine candidates, with good safety profiles and promising immunogenicity, which must be tested without delay in large scale phase III efficacy studies in South Africa in order to expedite the availability of a licensed preventative HIV vaccine, which is an important aspect of controlling the HIV epidemic in this country. Conducting multiple phase I/II studies requires the participation of several hundred, low-risk HIV negative, healthy volunteers and many ethical issues need to be addressed during the process to achieve this. An important ethical issue is the potential exploitation of communities and previously disadvantaged groups in South Africa participating in medical research, therefore it is essential to establish mechanisms to ensure transparent researcher-community-research participant interactions and provide a fully informed, low risk, HIV-negative cohort willing to be enrolled in specific phase I/II HIV vaccine trials. Potential participants and communities that are fully informed, in a transparent manner, about the risks and benefits of participating in HIV vaccine trials can make their own decisions about trial participation without fear of undue coercion and exploitation by researchers and vaccine manufacturers. A specific "prescreening protocol" was designed by PHRU-HAVD to channel willing HIV negative clients from a free adult voluntary counseling and testing (VCT) service into a structured programme called the "prescreening protocol", which is not HIV vaccine trial specific but is aimed at accumulating a cohort of potential volunteers for specific phase I/II trials as they become available. This recruitment protocol ensures that all potential HIV vaccine trial participants have the opportunity to lower their risk for acquiring HIV and other sexually transmitted diseases based on the advice received during risk reduction counseling sessions. In preparing for Phase III efficacy testing of promising HIV vaccine candidates, ethical issues concerning the potential cohorts that may be used and how efficacy will be established have arisen. Of great ethical importance is the proposed use of occupational cohorts, like gold miners that have historically been exploited, the participation of adolescents, the primary target group for an HIV vaccine and eventually also younger children and the equal distribution of men and women and individuals of all races in HIV vaccine research.