To expand postoperative residual lungs after pulmonary lobectomy, thoracic drainage with two chest tubes has been recommended. Several studies recently demonstrated that postoperative drainage with one chest tube (PD1) was as safe as that with two chest tubes (PD2). However, most of the patients in those studies underwent lobectomy by standard thoracotomy. Although the number of pulmonary lobectomies by video-assisted thoracic surgery (VATS) has been increasing in recent years, there have been no reports that compared PD1 with PD2 after pulmonary lobectomy, including that by VATS. To elucidate whether postoperative management with PD1 is as safe as that with PD2, we conducted a randomized controlled trial. Lung cancer patients who underwent lobectomies with mediastinal nodal dissection in our hospital were assigned to one of two groups: one chest tube placed in PD1 group and two chest tubes placed in PD2 group. A total of 108 patients were registered in the study. There were no significant differences in the age, gender, pathological stage or histological type between two groups. Since the residual lung expansion was good in both groups, there were no patients who needed thoracentesis. There were no significant differences in the number of cases with pleurodesis, the amount/duration of drainage or the pain of the patients between two groups. In conclusion, since PD1 has advantages in saving cost and time and in low risk of transcutaneous infection, PD1 is appropriate after pulmonary lobectomy by VATS and by open thoracotomy.