Offshore wind turbine (14) including a tower (1) rising above sea level (12) and one or ore blades (4), which can be put into rotation by wind. The offshore wind turbine includes a pump (6), which is adapted to pump sea water (13) up form the sea. At the delivery side the pump (6) communicates with nozzles (8, 9), said nozzles being adapted to direct sea water to the surface of the blades (4).