The morphology of the red blood cells (RBC) has been studied by atomic force microscopy (AFM) in contact with indicators of disturbed metabolism in experimental diabetes mellitus (DM) in rats. DM was modeled by administration of alloxan in a dose of 300 mg / kg body weight. After 1 month of DM modeling according to AFM data the RBC have an uneven surface, spinous outgrowths membrane. The proportion of such cells (echinocytes) was at DM 78.9% in the control group - 17.6%. RBCs of rats with DM also have a smaller diameter, a greater height and lower values of adhesion, compared to the control. The study of biochemical parameters revealed a pronounced hyperglycemia, and high levels of HbAlc, but the status indicators of oxidative stress (MDA, catalase, peroxidase), not significantly different in the two groups of animals. Thus, the AFM shows the violation morphology of RBC in experimental DM, leading role in the development of which plays hyperglycemia and glycation of proteins.