Of 1,164 (= 89.7%) of all diabetics established in the district department for diabetes Prenzlau the electrocardiograms in rest were evaluated and the frequency of hypertension, adiposity and left hypertrophy in the photofluorogram were registered. Altogether only 13% of all patients with an average age of 65 years had a normal ECG. In comparisons to the population with healthy metabolism the frequency of hypertension *84.0%), adiposity (62.7%) and in the ECG of repolarization disturbances (68.9%), myocardial infarction (6.4%), atrioventricular blockings (16.9%), absolute arrhythmia (4.4%), tachycardia (5.5%), a left hypertrophy (18.2%; in the photofluorogram 52.3%), of forms of bundle branch blocks (9.1% left-anterior hemiblock, 4.5% right bundle branch block and 3.1% left bundle branch block) and of an overturned left type (13.1%) were evident in diabetics. Pathological changes of the ECG could be proved no more infrequently in females with diabetes than in males with diabetes. The connection between the appearance of a coronary arteriosclerosis and the intake of tolbutamide supposed by the UGDP-study could be confirmed also for the intake of glibenclamide.