Limited studies have been performed on the association of distorted folates metabolism genetic markers with progression of clinically manifesting chronic heart failure with preserved ejection fraction (CHF-pEF) in patients with arterial hypertension (HTN) and type 2 diabetes mellitus (DM2).Objective. To identify folate cycle genes polymorphisms in patients with HTN, DM2 and CHF-pEF.Design and methods. We have identified the occurrence frequency of several MTHFR genes polymorphisms: 677 C > T (rs1801133), MTHFR: 1298 A > C (rs1801131), MTR: 2756 A > G (rs1805087), MTRR: 66 A > G (rs1801394) in patients with CHF-pEF and DM2 (n = 52), chronic heart failure with reduced ejection fraction (CHF-rEF) and DM2 (n = 49) and control patients without CHF or DM2 (n = 66). Mean aged was 69,9 ± 10,1 years old.Results. In comparison to the controls, the CHF-pEF group showed higher frequencies of rs1801133: CHF-pEF group — 61,54 % vs. 28,57 % (odds ratio (OR) — 4,0, confidence interval (CI) — 1,788–8,948, p < 0,002); rs1805087–75,0 % vs. 25,0 % (OR — 9,0, CI — 3,573–22,673, p < 0,001), rs1801394–90,38 % vs. 69,39 % (OR — 4,2, CI — 1,375–12,510, p < 0,017). Compared to the CHF-rFV group, the following frequencies were found: CHF-rFV — rs1805087–75,0 % against 36,96 % (OR — 5,2, CI — 2,110–12,414, p < 0,001), rs1801394–90,38 % vs. 68,75 % (OR — 4,3, CI — 1,414–12,909, p < 0,011). The polymorphism frequencies in CHF-rFV were generally comparable with such of the controls. Conclusions. Higher frequencies of rs1801133, rs1805087 and rs1801394 polymorphisms were detected in patients with HTN, DM2 and those with CHF-pEF, as compared to either helthy patients and those with reduced ejection fraction. There is also high rate of rs1801394 polymorphism in patients with HTN, DM2, regardless of the ejection fraction.