Scintigraphy with 99mTc-pyrophosphate during bicycle ergometry has been undertaken in 32 patients with myocardial infarction in the early phase of its healing. There were 3 scintigraphic investigations: one during bicycle ergometry and two control ones - before and the day after the test. The determination of changes in the degree of 99mTc-pyrophosphate accumulation under the influence of the exercise in patients with myocardial infarction in the early phase of its healing permitted the authors to detect several variants in the time course of scintigraphic values. Drop or rise of concentration of the labelled pyrophosphate at the height of the bicycle ergometry test compared to the data obtained prior to it are apparently due to changed bloodflow in the focus of lesion during exercise. Changes in the character and intensity of accumulation of the radiodrug after bicycle ergometry can be explained in the majority of cases by increase of metabolic disorders in the myocardium, supervening during the exercise, and in some patients, possibly, to sustained decrease of bloodflow in the affected area of the cardiac muscle.