Objective. To analyze contamination of surgical wound during tracheal resection depending on the mode of mechanical ventilation. Material and methods. There were 976 patients. Circular tracheal resection was made in 396 of these patients. Results. Overall postoperative morbidity was 15.7%, mortality — 0.8%. Bacteriological examination of surgical wound was performed before tracheotomy and after formation of anastomosis depending on the method of mechanical ventilation. Surgical field was sterile before tracheotomy in all cases, contamination was confirmed after tracheotomy in all patients. Minimal contamination was observed in case of apneic oxygenation (100 times less than volumetric mechanical ventilation or high frequency mechanical ventilation). In all cases, several species of pathogenic microorganisms were identified. The number of species was also minimal in case of hypnotic mechanical ventilation. Conclusion. Contamination does not directly affect the development of local purulent-inflammatory process. However, this factor should not be ignored and compliance with all preventive measures is required.