Several methods have been used to keep air way, but tracheostomy is the most safe and popular method for maintaining it. Tracheostomy has rare complications, but some authors stated 10~40% complication, and among them mortality rate is 0.9~2.8%. Wound infection of the tracheal stoma is one of the complications, which is the predisposing factor of pulmonary infection and therefore a contributing factor of mortality rate. Up to date, several authors reported serial results of bacteriologic cultures from tracheal stomas and sensitivity tests, but the prophylactic antibiotic therapy gave no satisfactory result to prevent pulmonary infection, especially when Gram negative infection. Recently from Apr '78 to Apr '80 in our dept. we surveyed bacterial culture and sensitivity test to get the knowledge of recent bacterial strain in it and the most sensitive antibiotics.