To review the recent literature related to pulmonary function testing and how it relates to the preoperative evaluation.There is increased interest in the field of pulmonary arterial hypertension. It is important to determine the clinical implications of this disease and determine whether preoperative therapy is indeed effective. Also, there is a need for the development of new noninvasive diagnostic techniques to identify patients at risk of pulmonary arterial hypertension.Pulmonary function testing can be used to quantify lung function, confirm an individual's functional status, evaluate regimen effectiveness, and determine disability. They may be essential in all candidates for lung resection. However, there are limits in the current testing of pulmonary function. There is new evidence that exercise testing may provide better diagnostic and prognostic information about patients with cardiovascular and pulmonary disease.