Objective: To compare the clinical effect and toxicities of preoperative concurrent chemoradiotherapy (CT/RT)with radiotherapy (RT) alone in patients with superior sulcus lung tumor. Methods: Fifty-six patients with superior sulcus lung tumor were divided randomly into two groups: twenty-six patients received concurrent chemoradiotherapy, the other thirty patients received only radiotherapy. For both groups, the same radiation technic was given with the convention fraction. The total dose was 45 Gy/25 Fr/5 Wk. For the CT/RT group, the patients were also given with concurrent chemotherapy (navelbine 15-18 mg/m2 on the 1st and 8th day, cisplatin 60 mg/m2 on the 1 st day). Results: The rate of complete resection in the CT/RT group was significantly higher than that in the RT group (92.3% vs 80%, P ＜ 0.05). The complete pathological response rate and 2-year survival rate in the CT/RT group were significantly higher than those in the RT group (P ＜ 0.01, P ＜ 0.01). The incidences of grades Ⅲ-Ⅳ radiation esophagitis and leukopenia in the CT/RT group were significantly higher than those in the RT group (23.1% and 23.1% vs 6.7% and 0, P ＜ 0.01, P ＜ 0.01). Conclusion: Preoperative concurrent chemoradiotherapy has the potential of improving the survival rate of superior sulcus lung tumors. Though this treatment regimen also increases the acute toxic effect, all patients can tolerate it. It is expected to be a new "standard treatment" for this malignant tumor.