Although the incidence of cases with the original indications for lung isolation such as abscess and hemoptysis has decreased, lung isolation is required with increasing frequency in an ever-widening spectrum of clinical situations. The preference of anesthesiologists has oscillated between bronchial blockers and single or double-lumen tubes for the past 50 yr. At present, double-lumen tubes continue to have the widest application for providing safe reliable lung separation in the majority of cases. However the optimal method of lung isolation in any individual case will depend on multiple factors which include the patient's underlying pathology and anatomy and the skill and training of the anesthesiologist.