In this experiment, sound‐pressure levels of the noise in a diving chamber, which was pressurized to a depth equal to 100 ft of sea water, were measured. In the first of two dives, measurements were taken during compression and decompression with a piezoelectric microphone oriented so that it was approximately in a horizontal line with the diver's ear and facing away from the vent. In the second dive, the microphone was at the same position in the chamber, but hanging downward at the diver's ear level. The microphone was previously calibrated under pressure using a reciprocity calibration technique. Measurements were taken with an octave‐band noise analyzer located outside the chamber. The results indicate that the noise levels were highest in the frequency range between 300 and 4800 Hz. Hyperbaric noise levels are discussed in relationship to recently proposed damage risk criteria for exposure to noise.