Sounds in the low audiofrequency region produced by marine life have been recorded at the U. S. Navy SOFAR Station, Kaneohe Bay. The SOFAR hydrophones are located at a depth of 2100 feet on the eastern underwater slope on the island of Oahu. These sounds have levels of the order of 1 microbar, and many have a rather musical quality. There is a marked seasonal variation in the production of these sounds, with the early spring months being the period of most frequent occurrence. This variation is coincident with the seasonal variation of whales in the area, and this feature, plus the characteristics of the sounds themselves, has led to the belief that they are produced by whales—with possibly an assist or two from porpoises. The sounds are described, and information is presented on their spectrum, sound level, and frequency of occurrence.