Residues of XDDT, XHCH and HCB in the fat of deer coming from the Białystok and Suwałki districts were determined. An average content of chloroorganic pesticides in the fat of wild boar, roe-deer, stag and elk (in mg/kg) was 0.146, 0.057, 0.027 and 0.028 consecutively of XDDT; 0.003, 0.005, 0.004 and 0.005 of XHCH; 0.003, 0.005, 0.003 and 0.005 of HCB. They were found to be lower than the analogous residues in the years 1987-1989.