Patients with early stage lung cancer including stage I, II, and IIIA consider lung surgery as a treatment. Postoperative pulmonary complications, such as pneumonia, atelectasis, worsened gas exchange, bronchoconstriction, thromboembolic disease and respiratory failure, sometimes occur and they lead to admission of intensive care unit (ICU) and increased length of hospital stay. There have been previous studies discussing the effect of preoperative pulmonary rehabilitation in thoracic surgeries, and it is widely known that preoperative pulmonary rehabilitation could benefit the outcomes of thoracic surgery. However, there are only few studies discussing the parameters affecting surgical complications. The purpose of this study was to investigate factors associated with the complications after lung surgery in the patients with early stage lung cancer, to help decide the patients who need preoperative pulmonary rehabilitation. Medical record of patients with lung cancer of stage I who received operation in our hospital from March to June 2018 were reviewed, and the result of pulmonary function test (B=-2.03, p=0.00) and type of operation (B=-2.50, p=0.02) were shown to influence the length of hospital stay. According to the results, we conclude that these factors should be considered when deciding the need of preoperative pulmonary rehabilitation to reduce complications of the lung surgery.