This article reports on selected presentations at the 6th International Conference on Human Herpesvirus (HHV)-6 and -7, organized by the HHV-6 Foundation. The 98 presentations--which explored in some detail the biology of HHV-6, chromosomally integrated HHV-6, diagnostic testing and manifestations of HHV-6 infection in disease. Associations between HHV-6 and -7 and a wide variety of diseases were reported, and are made plausible by the remarkably broad cellular tropism of the viruses in vitro. To determine whether these associations are causal, it is imperative to improve diagnostic technologies and to expand studies of possible disease associations. It also is important to expand on recent encouraging work identifying effective in vitro treatments for both HHV-6 and -7.