The management of patients suspected of having ventilator-associated pneumonia (VAP) requires a strategy for diagnosis and treatment that is designated to: (1) identify patients with true lung bacterial infection; (2) determine the pathogen(s) responsible for pneumonia; (3) permit early selection of appropriate antimicrobial therapy; and (4) avoid indiscriminate administration of antibiotics. The use of bronchoscopic techniques to obtain bronchoalveolar lavage (BAL) specimens from the affected area in the lung allows definition of a strategy superior to that based exclusively on clinical evaluation. When BAL is performed before introduction of new antibiotics, it enables physicians to identify patients who need immediate treatment and help to select initial antibiotic therapy (with the results of direct examination of BAL liquid) and to withhold, deescalate, and/or optimize treatment (when the results of quantitative cultures are available), in a manner that is safe and well tolerated by patients. This strategy, based on clinical and bacteriological evaluation, prevents resorting to broad-spectrum drug coverage in all patients who develop signs and symptoms suggestive of pneumonia, thus minimizing the emergence of resistant flora, and redirects the search for another infection site.