A cohort study representing a general population (Minorca Island, birth year 1997-1998) showed that in utero transfer of organochlorine compounds (OCs) in children was strongly correlated with the age of the mother and, in the case of hexachlorobenzene (HCB), 4,4'-DDE, and 4,4'-DDT, with the maternal body mass index. Some of these correlations remained significant for the serum concentrations collected in these children at four years. No significant correlations with length of gestation were observed. Breastfeeding and age of lactation were strong determinants of most OC concentrations at four years of age. At this age, the body burden of these compounds was higher than at birth irrespective of maternal or formula feeding, but they accumulated at higher extent in the former case involving concentration increments in blood that surpassed the growth dilution effects, with the only exceptions being pentachlorobenzene (PeCB), HCB, and 4,4'-DDT. 4,4'-DDE exhibited the highest increase in association with breastfeeding, pointing to a specific accumulation pathway via this mode. Compounds with low K(ow) values such as beta-hexachlorocyclohexane showed significant accumulation in four-year-old children but with small differences between the groups that had been raised on either breast milk or formula. Compounds having low K(oa) values such as HCB showed decreases in concentration and small body burden variation between birth and four years of age, which points to their preferential elimination in these initial periods of infant growth.