Abstract: We determined the residues of dichlorodiphenyl trichloroethanes (DDTs) in 6 species of commercial fishes from Dongguan and its adjacent waters by Agilent 7890N GC, capillary column (HP-5 30 m×250 μm×0.25 μm) and ECD detector. Results show that the DDTs residues in those fishes are 1.527~24.842 μg·kg^-1. Coilia mystus has the highest content of DDTs residues, followed by Uroconger lepturus and Harpadon nehereus. The average content of P, P'-DDE, P, P'-DDD, P, P'-DDT and O, P'-DDT is 44.55%, 29.19%, 22.01% and 4.25%, respectively. Since no new pollution source of DDTs was found, the DDTs in those fishes might come from the past pollution and pose no significant threat to human health.