The concentration of several chloro-organic derivatives as PBC, HCH isomers, HCB, and DDT and its metabolites was assayed in the human milk. Sixty two samples collected from 15 human milk donors from Warsaw and surroundings were studied. The results show, that PCB is present in the most elevated concentration in comparison with the remaining compounds (mean 0.0241 mg/dl of milk or 0.723 mg/kg of fat). Substantial differences in halogenated hydrocarbons excretion with human milk were noted during lactation. However no correlation between the amounts of excreted fat and these compounds levels in the milk was seen. No tendency to the decrease of the excretion of assayed compounds with milk during lactation was observed.