Hearing thresholds were measured for two subjects over a frequency range of 250 cps to 4000 cps. These measurements were made both in air and in water. When threshold intensity levels are compared, it is shown that the greatest loss in hearing acuity in water occurred over the frequency range from 500 cps to 2000 cps and amounted to approximately 20 db, while below 300 cps the threshold intensity in water was lower than that in air. Measured intensity levels for an underwater swimmer speaking into a face mask are also presented.