Continuous glucose monitoring - an important diagnostic, teaching and treatment tool for patients with diabetes mellitus, which is increasingly becoming a part of routine clinical practice in endocrinology. This article presents an overview of modern techniques, their advantages and disadvantages, evidence basis and place in everyday clinical practice. The article discusses the key factors affecting the efficiency, indications, contraindications, conditions of use of the continuous glucose monitoring systems in patients with diabetes mellitus, gives an algorithm for the application of this technique in clinical practice.