An attempt was made to understand how consecutive deliveries and the following lactations have an impact on the organochlorine compound levels detected in human milk. The other goal of the study was to check for a possible dependence between fat content and the levels of the studied compounds in milk samples from the same lactations. 199 milk samples were examined for the presence of p,p'-DDT, p,p'-DDE, p,p'-DDD, alpha-, beta-, gamma-HCH and sigmaPCBs. Moreover, in 87 milk samples the fat content was additionally determined. This study has indicated that, for the mother with a shorter interval between lactations, mean concentrations of the examined compounds were higher in the milk of the first lactation than that of the second. For the other donor whose second lactation began after 2 years, the mean levels of HCB, beta-HCH, p,p'-DDD, and PCBs in her milk were higher during the first lactation. At the same time, the concentrations of p,p'-DDT and p,p'-DDE after the second delivery were slightly higher. The correlation coefficients between the two data sets (fat content in milk, concentrations of the compounds studied in milk) showed no interrelationship between them.