Between January and April 2003, a sudden increase in positive respiratory tract specimens for Pseudomonas aeruginosa was observed in an intensive care unit of the University Teaching Hospital of Montpellier, France. Most of the strains were cultured from bronchoalveolar lavage fluid samples, suggesting that bronchoscopic procedures could be implicated. The relationships between isolates were investigated by antibiotyping and pulsed-field gel electrophoresis. Both phenotypic and molecular markers allowed identification of two consecutive nosocomial outbreaks of respiratory infections related to two different bronchoscopes. These two outbreaks implicated nine and seven patients, respectively. Four of these 16 patients had true infections and recovered with antibiotic therapy. Inspection of both bronchoscopes revealed a damaged internal channel caused by defective biopsy forceps. These defects led to improper cleaning and disinfection of the bronchoscopes despite adherence to all current reprocessing procedures. The two outbreaks were controlled after replacing the inner channels of the bronchoscopes and switching from use of re-usable to disposable biopsy forceps. These outbreaks emphasize the need to establish surveillance procedures for detecting contamination of bronchoscopes, and the importance of recording each endoscopic procedure to facilitate further investigations if needed.