PURPOSE: The aim of this study is to evaluate the effectiveness and surgical morbidity of preoperative chemoradiotherapy for locally advanced rectal cancer. METHODS: Between December 1997 and March 2000, 36 patients with locally advanced rectal cancer (clinical stage II or III) were treated with preoperative chemoradiation: bolus i.v. leucovorin, 20 mg/m2, plus 24-h continuous infusion i.v. 5-Fluorouracil, 425 mg/m2, Days 1-5, 29-33 and concurrent radiotherapy 4,500 cGy over 5 weeks. Surgery was performed 4-8 weeks after completion of the chemoradiotherapy. RESULTS: Grade 3-4 toxicity during chemoradiotherapy was low: hematological toxicities 2.8%, gastro-intestinal toxicities 5.5% and skin toxicities 8.3%. Complete response rate was 16.7% and partial response rate was 47.2%, the rate of downstaging for tumor was 65.5%. The overall rate of resectability was 94.1%. In 13 of 22 (59.1%) patients planned APR, the sphincter was preserved. The overall rate of surgical morbidity was 23.5%, but there was no postoperative mortality. One patient needed a reoperation because a complication may be associated with preoperative chemoradiotherapy. CONCLUSIONS: Preoperative chemoradiotherapy for locally advanced rectal cancer seems to afford some potential advantages: patients are able to tolerate higher chemotherapy doses with low toxicities; tumor downstaging and resectability rates are high; sphincter preservation is feasible; But perioperative morbidity has generally tolerable complications. And so we recommend the preoperative chemoradiotherapy may be one of the best treatments for locally advanced rectal cancer.