[Abstract] The present paper srudy the evolution of the lower part of the Tambre Basin duting the Neogene. The basin, the fluvial network and a group of features are analyzed, such as the asymmetry of the net, the entrenchement, steps, etc, that are present in the Tambre and also frequent in other fluvial systems of Galicia. Ir is settled down that the current configuration of the fluvial network has been reached after a complex system of captures, with inversion of the drainage directions. Such evolution is not presented like an anecdotic circunstance in the layout ofthe river but rather it is considered a remarkable example ofthe fluvial processes that have contributed to the modeling ofthe present relief of Western Galicia
