Our objective is to determine the importance of the genetic component of duration of life. Heritability of lifespan is measured in populations of Drosophila. Impacts of environmental factors (developmental factors, temperature, oxygen concentration, hypergravity, ...) is studied. This approach is important in both the prospective of a better knowledge of the factors affecting the duration of life (balance genes/environment) and the discussion of the evolutionary theories of ageing. Further researches will focus on (1) QTL mapping of genetical systems underlying ageing and (2) the effects of moderate stress on lifespan.