Aim. To evaluate the significance of potassium and magnesium in human health formation and their role in development of functional disorders of cardiovascular and nervous system and in development and progression of cardiovascular diseases. Materials and methods. Data from 55 literature sources published in Russia and abroad in the period of 1972-2018 years are reviewed. Results. Potassium has an important role in cells bioelectrical activity organization, cell action potentials formation and neuromuscular excitability and conductibility sustentation. Hypokalemia symptoms can be quite various. Frequent ones include neuromuscular conductibility disorders, various changes in cardiovascular system (myocardial contractile function decrease, blood pressure (BP) decrease, cardiac cavities dilatation). Potassium intake increase is followed by lower incidence of cardiovascular and cerebrovascular events, new cases of diabetes mellitus (DM) type 2, left ventricular hypertrophy, cardiac insufficiency, and arrhythmias. Magnesium is a universal regulator of biochemical and physiological processes in the body, a cofactor of more than 300 enzymes participating in biochemical reactions, and a natural physiologic potassium antagonist. It reduces potassium release from sarcoplasmic reticulum and protects cells from potassium overload in conditions of ischemia. Therefore magnesium reduces systemic and pulmonary vascular resistance that results in systemic BP reduction and moderate cardiac index increase. Also reliable evidence indicating moderate but clinically significant antihypertensive effect of magnesium medications was received. Magnesium deficiency is associated with increase of total cholesterol level, low-density lipoprotein, and triglycerides. Serum magnesium level is inversely proportional to the degree of cardiovascular disorders development risk, particularly of cardiac rhythm disorders and IHD complications. European Food Safety Authority (EFSA) confirmed that patients’ health status improved after a period of magnesium adequate intake. Even severe hypokalemia and hypomagnesemia often remain non-diagnosed in clinical practice. Medical practitioner of any kind should remember of potassium and magnesium deficiency clinical manifestations in order to manage it or prevent its development in patients with risk factors by adequate treatment assignment. Described potassium and magnesium interrelations as well as relatively high frequency and severity of combined deficit of these macronutrients justify advisability of the use of combined medications containing К+ and Mg2+in treatment of many disorders. An additional effect is observed when these electrolytes levels are corrected together. Conclusion. Control of electrolyte balance, first of all, of potassium and magnesium balance, should be an intrinsic part of present day clinical practice. In patients with high risk of hypokalemia and hypomagnesemia development either its correction in case of detection or prevention of potassium and magnesium deficiency development should be performed. Potassium and magnesium balance maintenance provides additional therapeutic effect in patients with AH, DM, congestive heart failure, IHD (including myocardial infarction), as well as in patients with high risk of stroke or severe ventricular arrhythmia development.