The report of the Epidemiology Subcommittee of the 2007 Dry Eye WorkShop summarizes current knowledge on the epidemiology of dry eye disease, providing prevalence and incidence data from various populations. It stresses the need to expand epidemiological studies to additional geographic regions, to incorporate multiple races and ethnicities in future studies, and to build a consensus on dry eye diagnostic criteria for epidemiological studies. Recommendations are made regarding several characteristics of dry eye questionnaires that might be suitable for use in epidemiological studies and randomized controlled clinical trials. Risk factors for dry eye and morbidity of the disease are identified, and the impact of dry eye disease on quality of life and visual function are outlined. Suggestions are made for further prospective research that would lead to improvement of both eye and general public health.