Organic chlorides have been known to accumulate, especially, in adipose tissue of human bodies. So that, it might be possible to expect chronically intoxicated patients due to an accumulative effect as far as pollution by organic chlorides becomes worse. We have known a certain relationship of the retaining concentration between in adipose tissue and in blood. The author has examined retaining organic chlorides in sera of healty subjects and patients with various disorder using a gas-chromatograph. Results 1) β-BHC, p,p'-DDT and p,p'-DDE have been shown in all the cases examined. 2) In healthy subjects, there was no particular difference in the contents of various organic chlorides depending on sexes, ages and farmer of nonfarmer group. 3) An average concentration of β-BHC was relatively high in the patients with liver damages, subacute myelo-opticoneuropathy, leukemia and malignant neoplasm. 4) β-BHC, p,p'-DDT and p,p'-DDE were higher in concentrations in the patients with malignant neoplasm than in healthy individuals and the patients with other diseases. 5) On the other hand, β-BHC, p,p'-DDT and p,p'-DDE were rather lower in concentrations in the patients with renal damages and aplastic anemia than in healthy individuals and the patients with other diseases. 6) The two jaundiced cases with hepatic illness showed highly concentrated p,p'-DDE, a main product of DDT. From the above observations, it can be said that organic chlorides will be accumulated in a certain extent in the tumors, although one was not able to demonstrate its effect on hematopoiesis. It is, however, uncertain as to whether or not organic chlorides are related to carcinogenesis. One can assume that liver damage will be the more increased, in future, the more pollution due to organic chlorides is progressed.