Objective. To study the relationship between glycemic control, hypertension, and macrovascular complications in patients with type 2 diabetes mellitus (T2DM). Subjects and methods. The clinical and epidemiological study enrolled 528 patients (30.5% men, 69.5% women) aged 30–69 years with T2DM. Glycosylated hemoglobin levels of ≥7% were regarded as diabetic decompensation. All the patients underwent a questionnaire survey, clinical examination, atropometric and hemodynamic measurements, ECG at rest, EchoCG, and determinations of carotid intima-media thickness (IMT), ankle-brachial index, and the type and extent of blood flow disorders in the segments of the lower extremity vessels. Cardiovascular diseases were verified through the survey and clinical examination and by medical records. Results. With inadequate control of diabetes, hypertension was more common (83.5%) and there was a significantly greater severity of the latter (p = 0.023) and ECG and echoCG signs of left ventricular hypertrophy. Few patients received long-term antihypertensive therapy, most of them had the therapy as course treatment and during elevated blood pressure. In this group of patients, there were more cases of angina pectoris (in 7% as evidenced by the survey), ECG signs of coronary heart disease (26.7%), ECG signs of aortic atherosclerosis (46.7%), prior myocardial infarction (6.1%) and its ECG signs (37.1%), as well as hypokinesis (33.3%) and akinesis (21.0%). Poor glycemic control was associated with the frequent occurrence of rhythm disturbances (22.2%), chronic heart failure (40.0%), diastolic (54.9%) and systolic (20.6%) dysfunction. The incidence of stroke (5.2%) and the rising severity of carotid stenosis increased with decompensated diabetes, as well as increased IMT was also noted. In the lower limbs, the main type of blood circulation was determined, the severe types of stenosis increased at the periphery, impaired blood flow was noted mainly at the subcompensation stage, and this was seen in the popliteal-and-ankle segment at the decompensation stage. Conclusion. With inadequate control of the glycemic status, macrovascular complications and hypertension were recorded more frequently in patients with T2DM. To optimally manage diabetes and prevent the development of complications, it is necessary for physicians of various specialties to apply an adequate team approach to sick patients and to improve the work of a diabetes school.