Among the greatest achievements of the 20th century, prolongation of life expectancy has been the result of improved health conditions, decreased childhood mortality, lower incidence of infectious diseases. The consequence is the rapid ageing of the world population, with the elderly representing over 25% of the entire population by the year 2030, of which 75% living in less developed countries. Ageing thus represents one of the major public health challenges of the 21st century. Indeed, unhealthy ageing and frailty of the aged population has an important impact on the economic development and social costs of a country, a problem even more acute in less developed countries. A better knowledge of immune senescence and the design of customised vaccination strategies for the elderly are the immediate challenges posed to scientists and physicians. The conference "Ageing and immunity", recently held in Siena (Italy), has addressed these issues and defined the global strategic priorities for research and health policies aimed at ensuring healthy ageing.