Subjective-harmonic amplitudes between ears, listeners, and frequencies are basic data relevant to several clinical and theoretical issues. Monaural tone-on-tone masking measurements for the second and third harmonics of 250, 500, and 1000 Hz have been obtained at 75 dB SPL from each ear of 8 subjects with normal bilateral hearing. The estimates of the corresponding aural harmonic amplitudes tend to: (1) be lower at the third than second harmonics, (2) differ nearly as much between ears as subjects, (3) correlate with overall masking levels across but nol within frequencies, and (4) increase slightly with fundamental frequency. These latter two findings are particularly interesting: (3) because such a correlation implies a previously unsuspected nonindependence of the distortion and masking processes, and (4) because such increases are inconsistent with the simple power-series description of aural distortion. Sensation level of the fundamental may mediate these increases in both masking and distortion. [Work supported by NIH and the Department of Otorhinolaryngology, University of Michigan Medical School.]