Abstract: A peripheral pump-turbine including two wheels meshed with one another, laterally incorporating two or more blades fitting in matching recesses intercalated between said blades, being housed in a casing provided with fluid intake and discharge openings, where the wheels can incorporate teeth arranged between the blades and the recesses to allow the meshing thereof, and where the wheels can mesh by means of pinions integrally coupled to the shafts thereof in the outer portion of the casing.