The content of chlorinated fat-soluble aromatic hydrocarbons was determined in fish from an area polluted by industrial effluents. The fish species investigated were selected among those used for human consumption. For some samples, both the fillet and liver were investigated. For others the whole fish was used. The following compounds were analysed and quantified: Trichlorobenzene, tetrachlorobenzene, pentachlorobenzene, hexachlorobenzene, heptachlorostyrene, octachlorostyrene and polychlorinated biphenyls. The results idicate an appreciable accumulation in fish of the higher chlorinated compounds as pentachlorobenzene, hexachlorobenzene, heptachlorostyrene and octachlorostyrene. Other chlorinated hydrocarbons as decachlorobiphenyl, pentachloronaphthalene, hexachloronaphthalene and hexachlorostyrene were identified, but not quantified. The total content of fat-soluble chlorine was determined in some samples before and after sulphuric acid treatment. The content of chlorine in the identified and quantified compounds accounted for between 40 and 100 per cent of the total amount of chlorine present in the samples as persistent (sulphuric acid resistant) compounds.