OBJECTIVE The concept of double primary lung cancer (DPLC) has been generally accepted. Recently, an increasing incidence of synchronous DPLC has been reported, while the diagnostic standard and treatment strategies remain to be improved. This study was conducted to investigate effective surgical treatment and prognosis of synchronous DPLC.METHODS From January 1983 to April 2004, 31 patients with synchronous DPLC were operated in our department. Clinical data, such as surgical pattern, postoperative complications, and survival status, of all these patients were reviewed retrospectively.RESULTS The 31 patients with synchronous DPLC accounted for 0.67% of all the 4,649 patients operated for primary lung cancer in our department during the same period. Both tumors of the synchronous DPLC were resected with Iobectomy or pneumonectomy in 12 patients, while among the other 19 patients at least 1 tumor was treated with partial pulmonary resection. The postoperative morbidity was 29%(9/31), including 1 case of respiratory insufficiency, 3 cases of atelectasis, 2 cases of atrial fibrillation, 1 case of haemoptysis, 1 case of pleural effusion, and 1 case of wound fat necrosis.No deaths occurred during the operations or within 30 days postoperatively.The postoperative 1 -, 3-, and 5-year survival rates were 52%, 29%, and 20%, respectively.CONCLUSION The incidence of synchronous DPLC is low. An aggressive and reasonable surgical approach can achieve a satisfactory outcome in patients with synchronous DPLC. The postoperative morbidity is low. Some patients might achieve long-term survival.