The following pesticides were identified in the sediments: a-HCH, Lindane, Heptachlor, Aldrin, pp ' -DDT, pp ' -DDE, and pp ' -DDD. The results show variation in both POC distribution and concentration when comparing pristine and urban lakes. It is important to note that pp ' -DDE (range: b.d.l. - 1.68 ng g(-1) d.w.) and pp ' -DDT (range: b.d.l. -0.89 ng g-1 d.w.) were present in three of the four lakes in the study. The statistical analyses showed significant correlations between pp ' -DDE and pp ' -DDD. Correlations between pp ' -DDT and its metabolites were not detected. The PCA showed groupings of some of the organic compounds based on concentration and degradation over time. It is concluded that Laguna Chica de San Pedro is the lake with the highest concentration of POC's, although the levels appear low when compared with those measured in pristine areas in Southern Chile.