Age-dependent immunological alterations are responsible for a large number of diseases in the elderly. It was the aim of a Symposium held in Kuhtai, Austria, from December 3-5, 1998, to bring together basic scientists, clinicians, and representatives of pharmaceutical companies to discuss immunosenescence and its consequences. Strategies were worked out for applying recent research results to the prevention and treatment of diseases in the aged and for organizing collaborations between teams throughout Europe within the 5th EU Framework Programme.