Abstract: Objective : To study the effect of external radiotherapy on unresectable superior sulcus tumors. Methods : Forty-seven patients with unresectable superior sulcus tumors treated with radiotherapy between January 1983 to December 2002 were reviewed. Thirteen patients had stage II b,25 stage Ⅲb and 9 stage Ⅳ diseases. Radiotherapy (RT) was given to all patients to a total dose of 14Gy~99Gy(median 70Gy), with 8 patients less than 50Gy and 39 more than 5Gy. Results : Tumor regression was achieved in 26 (55.3%)patients. Pain relief was achieved in 81.8% patients,with a median duration of 5 months (2~23 months). The overall survival at 1,2,3 and 5 years was 24.7% ,7.7% ,3.8% and 0%(median, 8 months). The median survival time (MST) for patients with stage IIb,Ⅲb and Ⅳ was 12 months, 8 months and 5 months, with the difference insignificant (P=0.552". For the 38 patients with stage IIb and Ⅲb, the MST was 6 months for patients with stable diseases after radiotherapy as com-pared with 11 months for those having achieved regression, with the difference significant (P=0.0003).The MST was 16 months for patients free from pain, 9 months for those with pain relief and 7 months for those with persistent pain, with the difference significant (P=0.016). The MST was 3 months and 9 months for patients who received the dose of <50Gy and ≥ 50Gy, with the significant difference (P=0.0085). Conclusion : Radiotherapy is useful for palliation in patients with unresectable superior sulcus tumors, Patients who received higher dose, achieved tumor regression and pain relief have an improved survival.