Surgical resection remains the mainstay of treatment for pulmonary malignancy. The ability of patients to undergo resection is dependent on the anatomic characteristics of the tumor, and the respiratory and cardiovascular status of the patient. There have been recent advances in our understanding of respiratory function in the patient with marginal lung function that have allowed surgical therapy of lung cancer in patients previously deemed inoperable. This review will define the marginal patients who can safely undergo pulmonary resection.