This review article is devoted to changes in heart rhythm against the background of type 2 diabetes mellitus, which is one of the most common endocrine diseases. In recent years, there has been an increasing association between type 2 diabetes mellitus and heart rhythm disorders. Arrhythmias such as tachycardia, bradycardia and atrial fibrillation are common in patients with type 2 diabetes and can have serious consequences on health and quality of life. Type 2 DM is increasingly common worldwide due to the rise in sedentary lifestyles, overweight, abdominal forms of obesity, and diets containing too much fat and carbohydrates. Insulin-independent diabetes is a metabolic disease responsible for autonomic neuropathy of the heart that affects both sympathetic and parasympathetic fibers, which can be explained by the adverse effect of blood glucose levels on heart rate variability (HRV). Although the gold standard is cardiovascular reflex tests to assess cardiovascular autonomic neuropathy, one of the most important is the measurement of heart rate variability (HRV). HRV is the variation between two consecutive contractions: the higher the variation, the higher the activity of the parasympathetic nervous system. A high HRV reflects the fact that a person can constantly adapt to changes in the microenvironment. Thus, low HRV is a marker of cardiovascular risk.