Samples of Pacific oysters, Crassostrea gigas, cultured in Deep Bay, Hong Kong, were collected for analysis of various heavy-metal contents: iron, copper, lead, cadmium, manganese, chromium, and zinc. In general, the gill had the highest metal contents, followed by the mantle, the viscera, with the smallest amount being observed in the adductor muscle. All metal contents obtained in the present study were within the range reported for the same species in areas where heavy-metal pollution is already recognized as a problem. A long-term monitoring program of measuring the contents of various metals in seawater, sediment, and oysters is therefore essential. Copyright © 1981 Published by Elsevier Inc.