Preoperative radiotherapy (RT) is recommended to many patients with localised rectal cancer, not previously treated with pelvic RT. However, the optimum fractionation, the timing of surgery and the best use of concomitant chemotherapy remains controversial. Short-course, preoperative RT may induce both acute and late morbidity and has been claimed to cause more morbidity than long-course preoperative RT. There are theoretical reasons to believe that RT given in larger fractions during a shorter period of time might result in more late side effects than giving a conventional, more protracted RT. In addition, the optimum timing of surgery after RT, with respect to postoperative morbidity, mortality and potential downsizing of the tumour is not known.