Aim To study the incidence and clinical and pathophysiological features of diastolic dysfunction (DD) and chronic heart failure with preserved ejection fraction (HFpEF) in patients with resistant arterial hypertension (RAH) associated with type 2 diabetes mellitus (DM).Material and methods A cross-sectional study that included 36 patients with RAH associated with type 2 DM (mean age, 61.4±6.4 years; 14 men) was performed. Measurement of office and 24-h blood pressure (BP), standard echocardiography with assessment of diastolic function (DF) and ventricular-arterial coupling, doppler ultrasound imaging of renal blood flow, and laboratory tests (blood glucose, glycated hemoglobin, blood creatinine, tumor necrosis factor α (TNF-α), brain natriuretic peptide (BNP), type 2 and type 9 matrix metalloproteinases (MMP-2 and MMP-9), tissue inhibitor of MMP 1 (TIMP-1), 24-h urine protein test, and 24-h urine volume test were performed for all patients. HFpEF was diagnosed according to criteria of the American Society of Echocardiography and the European Society of Cardiology 2019, and the Russian Clinical Guidelines on Diagnosis and Treatment of CHF 2017 and 2020.Results All patients had DD. Incidence of HFpEF detection according to the Russian Guidelines 2017 was 100%; according to the Russian Guidelines 2020, that included a required increase in BNP, and according to the criteria of the European Guidelines 2019, this incidence was 89 %. In 55.6 % of patients, DD corresponded to grade 2 (pseudonormal type). According to the correlation analysis, the DF impairment was associated with increases in pulse BP, myocardial mass, arterial and left ventricular elastance (arterial wall and left ventricular elasticity), basal glycemia and DM duration, MMP-2 level, proteinuria, blood creatinine, renal vascular resistance, and also with decreases in 24-h urine volume, MMP-9, TIMP-1, and TIMP-1/MMP-2. Significance of the relations of mean E / e' ratio with nighttime pulse BP, MMP-9, and 24-h urine volume were confirmed by results of multiple linear regression analysis. Increased myocardial and vascular wall stiffness, concentrations of MMP-2 and TNF-α and reduced 24-h urine volume were associated with progressive impairment of DF.Conclusion The combination of RAH and DM-2 is characterized by an extremely high incidence of DD that determines a great prevalence of HFpEF. The development and progression of DD in such patients are closely related with a complex of metabolic, proinflammatory and profibrotic biomarkers, increased vascular wall stiffness, pronounced left ventricular hypertrophy, and with structural and functional alterations in kidneys.