Hearing thresholds for pure tones between 16 and 30 kHz were measured by an adaptive method. The maximum presentation level at the entrance of the outer ear was about 110 dB SPL. To prevent the listeners from detecting subharmonic distortions in the lower frequencies, pink noise was presented as a masker. Even at 28 kHz, threshold values were obtained from 3 out of 32 ears. No thresholds were obtained for 30 kHz tone. Between 20 and 28 kHz, the threshold tended to increase rather gradually, whereas it increased abruptly between 16 and 20 kHz.