A total of 93 patients with rectal cancer treated with radiotherapy at department of Radiation Oncology, Yonsei University College of Medicine, Yonsei Cancer Center between January 1974 and December 1983 are retrospectively analysed. The patients are divided into three groups as follows: I. Postoperative radiotherapy, II. Postoperative recurrent, III. Unresectable or Inoperable group. In postoperative radiotherapy group, overall 5 year survival rate is $34.8\%$ and prognostic factors are presence of obstruction and degree of differentiation. In postoperative recurrent group, overall 2 year survival rate is $7.4\%$ with median survival of 13 months and prognostic factors are RT responsiveness and sex, and the local failure rate is $22.7\%$. In unresectable or inoperable group, overall 2 year survival rate is $19.8\%$ with median survival of 12.6 months and prognostic factors are RT responsiveness and RT dose. The complications for RT are not significant and are acceptable in all patients.