Objective To evaluate the preliminary outcome of postoperative three-dimensional conformal radiation therapy(3DCRT)as compared with conventional radiation therapy(CRT)in stageⅢA non-small cell lung cancer(NSCLC).Methods From December 1994 to February 2002,114 such patients received postoperative radiotherapy in M.D.Anderson Cancer Center,with 63 patients in CRT group and 51 in 3DCRT group.The median radiation dose was 53.5 Gy/27f/5-6w and 52.8 Gy/26f/5-6w in CRT and 3DCRT group, respectively.Results The median follow-up time was 28 and 13 months in CRT and 3DCRT group.The 1-,2- year overaLl survival were 80%,62% and 93%,70%.The 1-,2-year disease free survival was 62%,44% and 58%,32% in CRT group and in 3DCRT group,respectively.There was no significant difference between CRT group and 3DCRT group in terms of overall survival,disease-free survival,local-regional control,distant metastasis-free survival or treatment-related complication.There was significant difference in the death cause between two group,with 4 patients having died of cardiac complication in the CRT group and none in the 3DCRT group.Conclusions Postoperative three-dimensional conformal radiotherapy can reach the same immediate results of conventional radiotherapy in stageⅢA NSCLC,with a lower incidence of cardiac complication. However,the long-term results need further follow-up.