Content of polyamines and some patterns of metabolism related to their synthesis and catabolism were studied in blood of patients with chronic myeloleukemia and chronic lympholeukemia. Free polyamines as well as activity of diamine oxidase were distinctly increased in blood, while concentration of total diamino acids was simultaneously decreased in blood serum of the patients as compared with that of healthy persons. Specific type of the quantitative alterations was responsible for efficiency of chemotherapy in these patients.