Aim. To assess the correlation of fibrosis biomarkers with parameters of diastolic function (DF) in assessing global longitudinal strain in patients with ST-segment elevation myocardial infarction (STEMI) and preserved left ventricular ejection fraction (EF).Material and methods. We examined 50 patients (100%) with primary STEMI and preserved LVEF at the end of hospitalization. On the 1st day of MI, standard diagnostic investigations were carried out. On the 12th day, the serum concentration of procollagen type I carboxy-terminal propeptide (PICP), N-terminal propeptide of procollagen type III (PIIINP), and galectin-3 was determined, as well as echocardiography was performed to assess left ventricular DF. After 1 year, all participants underwent reassessment of PICP, PIIINP, and galectin-3 serum levels. Echocardiography was also performed with an assessment of DF and LV global longitudinal strain.Results. According to speckle-tracking echocardiography, LV global longitudinal strain was visualized in 30 patients (60%), who were included in the final analysis. In the rest of the patients (40%), the limitations did not allow the technique to be performed. During the hospitalization, signs of diastolic dysfunction (DD) were detected in 5 (16,6%) patients; after 1 year, their number increased by 7 (23,3%). During the 1-year follow-up, the total number of patients with echocardiographic signs of DD was 20 (67%). At the same time, global strain parameters indicated the presence of DD in 23 (77%) patients. However, comparison of the incidence of DD according to echocardiography and using the speckle-tracking technology did not show significant differences (p=0,283). Throughout the entire follow-up period, the concentration of the studied fibrosis markers significantly exceeded the control group values. We recorded associations of global strain parameters with biochemical markers of fibrosis and LV DF indicators.Conclusion. Fibrosis biomarkers (PICP, PIIINP, galectin-3), assessed in the subacute period of MI in patients with preserved EF, correlated with indicators of global myocardial strain, which indicates the potential value of their determination for predicting and detecting DD in the postinfarction period.