The German Ageing Survey (DEAS) is a main source of information about ageing and old age as a stage of life in Germany. It is a nationally representative, cross-sectional and longitudinal survey of people in the second half of life (i. e. aged 40 and over).The comprehensive study of people in their mid- and older adulthood provides individual data for use both in social and behavioural scientific research and in reporting on social developments. The data is thus a source of information for political decision makers, the general public and for scientific research. The DEAS allows to form a comprehensive picture of life situations and life contexts of old and ageing people in Germany and to respond to current political and academic questions.