HealthGrid 2008 is the sixth conference in this series of open forums for the integration of grid technologies and its applications in the biomedical, medical and biological domains to pave the path to an international research area in healthgrids. The main objective of the HealthGrid conference and the HealthGrid Association is the exchange and discussion of ideas, technologies, solutions and requirements that interest the grid and the life-sciences communities to foster the integration of grids into health. Subjects in this publication reflect the diversity of mature practice: Advancing Virtual Communities, offering a glimpse of the kind of communities that are brought together by means of collaboration grids; Public Health Informatics, exploring the diffusion of grid concepts and technologies in health informatics; Translational Bioinformatics, the contact point between medicine, healthcare and genomics; and Knowledge Management and Decision Support, one direction that is confidently expected to grow as the synergy of grids and 'evidence-based practice' in healthcare is exploited.