The nosocomial pneumonia is the most prevailing form of hospital-acquired infection. It is the leading cause of mortality among all forms of hospital-acquired infections. In the departments of resuscitation and intensive therapy nosocomial pneumonia consists more than 25% of all hospital-acquired infections. The analysis of lavages of various components of apparatuses of artificial pulmonary ventilation in the departments of resuscitation and intensive therapy of surgery hospital departments demonstrated that gram-negative micro-flora inoculated more often (72.0%). During last years, this type of micro-flora plays leading part in development of severe forms of nosocomial pneumonia. The gram-negative bacteria consisted up to 38/8% of all isolated cultures. The similar micro-flora was isolated and from tracheobronchial lavages and it confirms the possibility of infection spreading by anesthetic breathing equipment.