SUMMARY. — Georges Canguilhem devoted only limited place in his various writings to the transformation of biology during the XXth century, in particular to the « molecular revolution ». He was fascinated by the models of cybernetics and the informational metaphors of molecular biology : this prevented him from realizing that the new vision of life which was being progressively constructed was very close to the rational vitalism that he was trying to outline throughout his life. The study of genetic diseases as well as the results obtained by the gene inactivation technology illustrate these new biological conceptions and their deep resonance with the major works of G. Canguilhem. The latter did not elaborate a philosophy of biology but a philosophy of life : this explains how he was able to anticipate the future transformations of this discipline.