A systematic account of the polychaete fauna of Wallis Lake, New South Wales, is given. Five new species are described belonging to the genera, Haploscoloplos, Barantolla, Euclymene, Lysilla and Rhinothelepus, the latter being a new genus. Introduction Wallis Lake is a salt-water coastal lagoon on the central coast of New South Wales. The lake is approximately 12 miles long and 3 miles across at its widest point. The maximum depth of water is 16 feet. The lake is continually open to the sea at its northern end at Forster. Two small creeks flow into the northern part of the lake, which carry large amounts of fresh water after periods of prolonged rain. All the polychaetes were collected from the eastern shores of the lake during December 1970, using a Smith-Mclntyre grab. Thirty-two species of polychaetes were found, of which six are new species, and one of these is placed in a new genus.