Background Metastatic lung cancer is one of the most common oncologic problems.This study aimed to evaluate the long-term clinical outcome of stereotactic body radiation therapy (SBRT) for metastatic lung tumors.Methods We retrospectively reviewed the 71 patients with lung metastases,who had 172 lesions treated with SBRT from January 2000 to December 2006.All patients were unfit or failed after surgery and/or chemotherapy.The median total dose was 48 Gy (range,30-60) in 4 (range,2-12) fractions.The median size of the irradiated lesions was 2.1 cm (range,0.9-7.9 cm).Results All but two patients received follow up.The median follow-up time was 24.7 months (range,2.9-114.4 months).The median follow-up time for living patients was 86.8 months (range,58.1-114.4 months).The 1-,3-,5-year local control and overall survival rates were 88.8％,75.4％,75.4％ and 78.9％,40.8％,25.2％.Multivariate analysis showed that the absence of extrapulmonary metastases (P=0.024; hazard ratio (HR),1.894; 95％ confidence interval (C/),1.086-3.303) and disease-free interval ≤12 months (P =0.014; HR,0.511; 95％ Cl,0.299-0.873) were independent prognostic factors.No grade 3 or more acute and late toxicities occurred.Only one patient developed a non-symptomatic rib fracture.Conclusion SBRT could be an alternative treatment to surgery for subsets of patients with lung metastases with favorable long-term survival and tolerable complications.