Introduction. The coronavirus disease has reached an alarming epidemic scale with extraordinary morbidity and mortality rates for the entire world population. The majority of patients with COVID–19 note damage to the respiratory tract and state a more severe course of the disease with the development of systemic damage. A more severe course of COVID-19 is associated with the presence of comorbid diseases. Aim. To investigate and analyze clinical and laboratory manifestations and to determine the main comorbidities of patients with COVID-19 infection. Materials and methods. The research was carried out in accordance with bioethical norms and rules. 179 patients with COVID-19 (the main group) and 42 people of the control group were examined. Diagnosis and treatment of the COVID-19 coronavirus infection was carried out taking into account the relevant national recommendations. The average value and standard deviation were statistically determined. The probability of differences was performed using the Mann-Whitney U-test and the Wilcoxon W-test of signed ranks. The threshold value of the level of statistical significance of all calculated features was taken as 0.05 (p=0.05). Results. A high comorbidity with cardiovascular system pathology was found – 40.2%, type 2 diabetes – 22.3%, respiratory system diseases – 20.7%. Disorders of the functional state of the cardiovascular system were determined: pulse values – 91.01±13.44, systolic (127.9±15.19) and diastolic (79.3±11.6) blood pressure. Changes in clinical blood analysis were noted: erythrocytes – 4.38±0.65 x1012/l, hemoglobin – 127.6±21.2 g/l, hematocrit – 0.37±0.07, leukocytes – 10.7±7, 32 x109/l, segmented (65.4±14.8%) and rod-nuclear (9.03±9.99%) neutrophils, platelets – 226.1±90.6 x109/l, lymphocytes – 20.24±12.43%, monocytes – 6.60±4.37% and erythrocyte sedimentation rate (ESR) – 25.4±14.9 mm/h. Significant (almost fourfold) increases in IL-6 levels (24.56±22.9 pg/ml) and blood glucose concentrations (7.40±3.42 mmol/l) were determined. Conclusions. A significant comorbidity of COVID-19 was determined and a significant prevalence of indicators of the functional state of the cardiovascular system and a decrease in the average levels of the quantitative composition of erythrocytes and indicators of hemoglobin and hematocrit were established. Significant leukocytosis, neutrophilia, lymphocytosis and monocytosis, significant excesses of ESR and IL-6 and blood serum glucose were determined, which confirmed the presence of a significant inflammatory reaction in response to infection with COVID-19.