A study was done of the bulk, the distribution and seasonal variation of the concentration of 22 cyclic organochlorines in whole soft tissue of five benthic species of the Valdivia river estuary (X Region, 39°49'S, 73°18'W), using capillary gas chromatography-electron capture detector. Six seasonal sampling over a two year period along the river were done to conduct this research. Low levels of the organochlorine compounds, close to the range between the limit of detection and the limit of quantification (0,02 ng/g and 0.10 ng/g for a 10 g wet sample, respectively) were determined for most of the samples. In Hemigrapsus crenulatus and Cancer sp. the highest concentrations corresponded to aldrin, 4,4′-DDE and decachlorobiphenyl (DCB) while in Chilina ovalis the highest concentrations were due to heptachloro, aldrin, 4,4′-DDE and DCB. Mytilus chilensis showed heptachloro, aldrin, heptachloro epoxide, 4,4′-DDE and DCB and Tagelus dombeii showed aldrin and DCB. The seasonal variation of the mean concentration of organochlorines by sample followed the tendency of the seasonal variation of the lipid content.