Major pulmonary resection is accompanied by a high rate of complications that prolong hospitalization and increase costs of medical care. Optimal evaluation of patients for lung resection continues to be a clinical challenge. An historical review of techniques for assessing pulmonary physiologic status in lung resection patients reveals that spirometry, when combined with some measurement of gas exchange such as diffusing capacity or oxygen consumption during exercise, provides reliable guidelines for selecting patients for major lung resection. Careful assessment of lung resection candidates can reduce operative morbidity and mortality and permits improved allocation of surgical and postoperative care resources.