Glomerular filtration was examined by way of a radioisotope technique using Yb169-labelled ethylenediaminetetracetic acid. The method permits to conduct the examinations without radio-isotope equipment at the bedside of myocardial infarction patients, which is of great practical convenience. The study was conducted in 65 myocardial infarction patients and in 14 control individuals. Glomerular filtration was studied dynamically in different age-groups, in patients with acute and recurrent myocardial infarction with due regard of concomitant hypertension and complications. A correlation of the disorders in glomerular filtration and the age of the patients was revealed. The lowest figures of glomerular filtration were received in patients with myocardial infarction complicated by circulatory insufficiency and, especially, cardiogenic shock. The indices of glomerular filtration correlated with the circulating blood volume and venous pressure not in all patients.