The concentrations of organochlorine pesticides (OCPs) in fish, shrimps, cattle fat and human serum samples from the Sene-Gambian region were measured using validated analytical methodologies. The results obtained were compared with those of other existing African studies and with data from other developing countries. In fish samples, p,p′-dichlorodiphenyldichloroethylene (p,p′-DDE) and HCB were detected with a frequency of 100%, whereas p,p′-dichlorodiphenyltrichloroethane (p,p′-DDT) was detected in eight, heptachlorepoxide in six and endosulfansulfate in five of the nine fish samples. Relatively low concentrations of OCPs were found in cattle and shrimp fat samples. p,p′-DDE and α-hexachlorocyclohexane (α-HCH) were the most frequently identified. The sum of HCHs ranged from undetected to 13.3 ng g⁻¹ fat, the sum of DDTs from 11.1 to 199.2 ng g⁻¹ fat and the sum of endosulfans from not detected to 49.7 ng g⁻¹ fat in fish and shrimps. In serum samples, α-HCH, p,p′-DDE, o,p′-DDT and p,p′-DDT were detected in all 16 pooled serum samples, whereas endosulfansulfate, methoxychlor, mirex, heptachlorepoxide and endrin were detected in 15 samples with most of the concentrations below 10 ng mL⁻¹. The concentrations of OCPs in human serum were given on a serum lipid and whole serum volume basis. The implications for the human diet of these OCP concentrations in serum were investigated by means of biomagnification factors related to the log K_ow values of the targeted compounds. The current use of HCH mixtures was suggested to explain the unusually high α-HCH concentration. The distribution pattern of these OCPs in humans was also discussed and compared with that in other studies.