Aim. To study molecular biomarkers in patients with type 2 diabetes (T2D) in combination with heart failure with preserved (HFpEF) and mid-range ejection fraction (HFmrEF) and compare the data obtained with clinical characteristics of myocardial remodeling.Material and methods. The study included 42 patients with T2D (men — 53%, mean age — 60 years) with clinical manifestations of class II HF: 29 patients with HFpEF (group 1) and 13 patients with HFmrEF (group 2). The control group consisted of 13 healthy people, which were comparable in sex and age and had a normal body mass index (BMI). Patients received stable glucose-lowering and optimal drug therapy for HF for 3 months prior to enrollment in the study. Patients with HFpEF and HFmrEF were comparable in clinical and demographic parameters, had glycated hemoglobin (HbA ) of 8,5% and 8,8%, respectively (p>0,05), increased BMI or grade I-II obesity.We studied following biomarkers: NT-proBNP, highly sensitive C-reactive protein (hsCRP), sST2, galectin-3, procollagen type I C-terminal propeptide (PICP), matrix metalloproteinase 9 (MMP-9), tissue inhibitor of metalloproteinase-1 (TIMP-1).Results. Volumetric parameters of the left ventricle (LV),LV mass indexed to growth and NT-proBNP were higher in the group of HFpEF patients (p<0,05 for all). The concentrations of galectin-3, PICP were higher, and the MMP-9/TIMP-1 ratio decreased in patients with T2D compared with the control group (p<0,05 for all). PICP values were higher in patients with HFmrEF compared with patients with HFpEF (106,4 (85,4; 140,4) ng/ml vs 46,8 (12,6; 98,6 ng/ml), respectively, p=0,043). In patients with T2D and HF, a relationship was found between TIMP-1 andLV end-diastolic volume (r=-0,68; p=0,042).Conclusion. Patients with HFmrEF and T2D have higherLV volume and mass, higher concentrations of NT-proBNP and PICP in comparison with patients with HFpEF. The direction of MMP-9/TIMP-1 changes may reflect a decrease in antifibrotic processes. Further prospective studies on large samples using a multiple biomarker model are required in T2D and various HF phenotypes.