Seventy male patients with a mean age of 56.8 years scheduled for pulmonary function testing were subjected to a stair climb in order to determine the relationship, if any, between the number of steps climbed and the results of pulmonary function testing. The number of steps completed was plotted against the different parameters which may be used as predictors of post-thoracotomy outcome. The stair climb acts as a stress test and, although there is a strong relationship to pulmonary function tests, it also is an indicator of many other parameters including cardiovascular status, cooperation, and determination. Based on results of this study, the stair climb can be used as a reliable screening test of pulmonary function. Also, preoperative patients who are unable to perform pulmonary function tests can be evaluated accurately for lung resection by use of the stair climb test.