Between December 1982 and October 1983 samples of human body fat were taken during routine necropsies carried out on 187 persons aged over 5 years and four infants aged under 4 months. Comparison of the results of analysis with those from the previous studies in 1976-1977, and earlier, shows a continuing decline in residues of p,p'-dichlorodiphenyltrichloroethane (p,p'-DDT) and dieldrin (HEOD) and a reduction in the amounts of p,p'-dichlorodiphenyltichloroethane [p,p'-DDE, a metabolite of p,p'-DDT] and hexachlorobenzene. The concentrations of other compounds were similar to those observed in the previous studies. The results show that the amounts of organochlorine pesticides and polychlorobiphenyl compounds contained in human fat samples from residents in the UK compare favourably with data obtained in other countries.