The Internet provides easy, widespread access to new developments in the field of medicine. The pace of HIV-related research is rapid and has global relevance, making the Internet a particularly well-suited technology for dissemination of information. The number of sites offering HIV-related information is vast, and the quality is variable. Nevertheless, access to reliable information can be a highly efficient method to acquire up-to-date knowledge about advances in HIV investigation. This review summarizes high-quality HIV-related Web sites, including sites that provide access to HIV-related guidelines, conferences with Web content, images, case studies, and clinical and scientific databases. Also included are HIV-related reference sites, Web sites for journals that publish regularly on HIV- and AIDS-related advances and epidemiology, and policy oriented sites. In addition, Web sites with materials for patient information and advocacy and specialty societies for HIV practitioners are listed.