The time course of the content of hexose fractions was compared with the size of the myocardial infarction appraised from the ECG and with the clinical course of the acute period of myocardial infarction in 100 patients. The degree and duration of the increase in the blood glucosaminoglycane content were determined by the size of the focus of myocardial damage and the severity of its clinical course. The extent of the damage to the myocardium was found to be in accord with the increase in the content of the fraction of glucosaminoglycane hexoses. The results of the study suggest that determination of the content of glucosaminoglycane hexoses in blood may serve as an index of the severity of the myomalacia processes in the myocardium. A decrease in the level of the fraction coincides in time with the average terms of the onset of reparative processes in the myocardium which are determined from the findings of pathology.