Magnesium (Mg) is essential element for cardiovascular system. Together with known increase in macronutrient deficiency prevalence, as well as the complexity of its assessment, it is relevant to identify independent risk factors and clinical manifestations of Mg deficiency in postmenopausal women with hypertension and heart failure with preserved ejection fraction (HFpEF). 140 postmenopausal women with hypertension and HFpEF were included in the study. According to the Mg retention test, 72 patients (group 1) had macronutrient deficiency, and 68 (group 2) did not have the one. Anamnestic data, patient complaints, as well as clinical examination features, including office blood pressure measurement, were studied. As result of the study, it was revealed that two or more pregnancies were more often recorded (15 % vs 4 %; p = 0.047) in patients with Mg deficiency, hypertension and HFpEF. Group 1 patients more often consumed salt (60 % vs 41 %; p = 0.015), sugar (39 % vs 29 %; p = 0.042) and used diuretics (22 % vs 7 %; p = 0.017), but less used Mg rich foods (18 % vs 31 %; p = 0.002). In addition, women with Mg deficiency were more likely to have such manifestations as chronic constipation (22 % vs 9 %; p = 0.037) and calf muscles cramps (38 % vs 21 %; p = 0.04). As result of logistic regression model constructing, it was determined that the Mg deficiency in postmenopausal women with hypertension and HFpEF is associated with the fact of excessive sugar intake, diuretics use, the presence of skeletal muscle cramps, but absence of excess salt intake and sufficient use of Mg rich foods demonstrates protective properties.