The atomic force microscopy (hereinafter - AFM) is one of the leading applications of Nanotechnological research methods of cell membranes widely used in key areas of biomedicine. The study of the biophysical properties of the membrane and morphological parameters of lymphocytes by AFM can provide essential information about the patterns of structural change of the cytoplasmic membrane in the development of diabetes, disorders of metabolism, microcirculation and immunity. The purpose of this study was to investigate a number of morphological and biophysical characteristics of blood lymphocytes of patients with diabetes mellitus by AFM. The material of the study was lymphoid cells of peripheral blood of patients with insulin-dependent (IDDM) and non-insulin dependent type of diabetes... mellitus (NIDDM), and healthy volunteers. For analysis of the membrane of lymphocytes was used a scanning probe microscope Solver P47-PRO (NTMDT, Russia). Scanning cell surface of the membrane of blood lymphocytes were performed using silicon probes series PNP-DB-20 (NT-MDT) with a hardness of 0.06 N/m, with the radius of curvature of 10 nm. AFM images of the cells were analyzed using the computer program Nova. Based on analysis of AFM images were determined morphological parameters of blood lymphocytes: diameter, height, area, volume; and biophysical parameters: Young’s modulus, strength, adhesion, roughness. The results showed that in Diabetes mellitus is a significant increase in membrane rigidity blood lymphocytes as compared to those of the blood lymphocytes of healthy people. The adhesion properties and surface topography of lymphocytes in different types of diabetes is differing. At patients with IDDM values of adhesion strength and roughness of cells is higher than in patients with NIDDM. The morphometric parameters of blood lymphocytes of patients with IDDM also exceed similar parameters in patients with NIDDM. Identified using AFM morphological and biophysical characteristics of peripheral blood lymphocytes of patients with different types of diabetes may have a pathogenic role in the development of immunologic disorders occurring in this disease.