Adjuvant chemoradiotherapy is the standard treatment in resected stage II/III rectosigmoid carcinoma. We report a retrospective analysis of 33 patients who received adjuvant chemoradiotherapy. Patients received 5-fluorouracil (375mg/m2/day x 5days) and calcium leucovorin (20mg/m2/day x 5days), q4weeks, two courses before and two courses after radiotherapy. The 5-fluorouracil dose was reduced to 225mg/m2/day given continuously as protracted short-term infusion on the first and last 3 days during radiotherapy. Radiotherapy was started at 7th week and 45-50.4 Gy was given to pelvic region. Median age was 63 years. Median follow-up was 38 months starting from the operation date. Four-year local and distant control rates were 78% and 69%, respectively. Four-year disease-free survival and overall survival were 60% and 62%, respectively. Protracted short-term infusion of 5-fluorouracil during pelvic irradiation is a safe treatment modality. Further studies are needed to improve the local control of high-risk rectal and sigmoid carcinomas.