The survey of the excretion concentration of various organo-chlorine pesticides in breast milk was performed on 3 districts in Wakayama prefecture. Tanabe City which is distant from Gobo. City adjoing Kawanabe-cho, was a relatively low contaminated district. The regional result is caused by the fact that the residents in Tanabe City were all housewives in non-farmer who were no contaminated by direct exposure to pesticides, and the intake of milk products and vegetables contaminated by pesticides in a food cycle was a relatively small quantity.