Public health problems associated with ageing, due to its complexity, enters the spheres of interests in many fields: demography, economics, and politics. In many countries challenges related to the increasing number of people at retirement age remain strongly dependent on the actual and projected numbers of people at productive age emerging from the demographic condition of the population. The article addresses the complexity of the relations between life expectancy, healthy life expectancy and the length of life in disability. Underlined are the social and economic conditions of life in the period of the old age, including the problem of inequalities in health and the role of research in the field of public health for the proper recognition of the problem and rational planning of resource allocation and organizational measures aimed at meeting social expectations associated with ageing.