Proliferative activity and differentiation levels of lymphocytes of lymph nodes and peripheral blood of practically healthy people and patients with chronic lymphocytic leukemia have been studied using the present physicochemical methods (autoradiography with labelled DNA and RNA precursors, microspectrocytometry, NMR spectroscopy, kinetic formaldehyde method, etc.). The following points have been stated: stage character of changes in normal and leukemic cells, differences in synthesis of nucleic acids in different periods of the cell cycle in norm and under chronic lymphocytic leukemia, proliferation peculiarities of lymphocytes in lymph nodes and in blood, presence of DNA defects in the process development, changes in lipids of lymphocytes and blood plasma at early stages of the disease and in the process of its development.