The invention relates to a freezer for biosanitary and cytotoxic waste, which comprises an inner space that houses a waste container, a front door through which the waste container is inserted into/removed from the inner space, an upper door through which waste is poured into the inner container, refrigeration means, and means for controlling the temperature of the inner space. The freezer further comprises an air purifier that treats an air current from the inner space when one of the doors is opened, thereby preventing the emission of chemical and biological pollutant particles into the exterior environment.