Abstract: This invention relates to a washing machine for dental instruments comprising a frame structure housing a tank which may be closed by a lid, supplying pipes of said tank with water through a water treatment apparatus. A draining pump for said tank is provided, and an agitator for the water in the tank. A cylinder is rotatively and removely mounted in the tank and has a support which receives the instruments to be cleaned. A control device comprising a timer, push-buttoms, valves and pressure gages controls the automatic washing cycle.