Abstract Samples of marine organisms derived either by direct capture methods in local waters, or by purchase from retail markets in Hong Kong, Kowloon and the New Territories, were analysed for between six and nine trace elements during 1976 and 1978. The results indicated significantly elevated concentrations of arsenic and cadmium in many samples. Whilst arsenic in marine organisms is not considered to be a toxicological threat to man, as the majority of this element is present in seafood in an organic form readily excreted by man, cadmium may be of significance as a human health hazard. The other metals studied were either only weakly elevated in certain classes of organism (lead) or only rarely attained levels which are considered a threat to human health (chromium, mercury). Antimony, copper, tin and zinc were also not present in high enough concentrations to cause detrimental health effects in the population of Hong Kong. Further monitoring of selected elements in seafood is considered necessary, both to delineate any temporal change in trace metal levels in locally available organisms and to ensure that concentrations of cadmium do not increase further.