This paper reviews the literature for evidence of links between ventilation rates in dwellings and moisture related respiratory health with a particular focus on house dust mites (HDM) and fungal growth. There is general consensus that a link exists between ventilation rates in dwellings and respiratory hazards (for example HDM). There is also general consensus of a link between these respiratory hazards and respiratory problems, but it is not clear to what extent hazards cause ill-health. Most existing data are inadequate for conclusions to be drawn whether ventilation rates directly cause respiratory problems. We discuss the many difficulties in attempting to establish these relationships, and suggest the need for larger studies.