In the first experiment reported here, for subjects with sensorineural hearing loss and tinnitus, the masking of tinnitus is primarily dependent on the masker intensity; masking is nearly independent of masker frequency. In the second experiment reported here, for subjects with normal hearing, the central masking of a continuous tone (used to stimulate the tinnitus) is primarily dependent on the intensity of a contralateral masker; masking is nearly independent of masker frequency. Implications of the flat tuning curves on the design of tinnitus maskers and one possible interpretation of the similarity of tinnitus masking and central masking are discussed.