Abstract: A oxygenator for oxygenating water in swimming pools. The oxygenator includes a chamber which has a port outwardly extending therefrom for drawing air into the chamber. A venturi is extended through the chamber. The venturi has opposite inlet and outlet ends, opposite generally frusta-conical inlet and outlet portions and an intermediate portion interposed between the inlet and outlet portions of the venturi. The intermediate portion of the venturi has a plurality of spaced apart apertures therethrough to permit passage of air in the chamber into the intermediate portion of the venturi.