Aerosolized tobramycin has been frequently used in cystic fibrosis patients in order to directly deliver the antibiotic to the endobronchial site of infection. Recently, we experienced three cases of severe chronic bronchial infection of Pseudomonas aeruginosa treated by aerosolized tobramycin inhalation (TOBI). For two cases, we succeeded in improving the patient's medical condition, quality of life, and reduced the amount of sputum. We consider that TOBI should be useful for chronic bronchial infection by Pseudomonas aeruginosa in the case of a patient who does not respond to usual antibiotics via other routes. But further investigation is necessary to reveal clinical efficacy and safety in non-CF patients with bronchiectasis.