The treatment of rectal cancer has changed over the last two decades as far as surgical techniques and radiotherapy are concerned. We studied the changes in patterns of care for patients with rectal cancer and the effect on prognosis. All patients with cancer of the rectum or rectosigmoid in South-east Netherlands, diagnosed in the period of 1980-2000, were included in our analyses (n=3635). The use of surgery as the only treatment decreased from 62% in the period of 1980-1989 to 42% in the period of 1995-2000, whereas the combination of surgery and radiotherapy increased from 26 to 40%. The use of postoperative radiotherapy decreased from 25 to 4%, while preoperative radiotherapy increased from 1 to 35%. Patients aged 75 years or older were less likely to receive radiotherapy. After adjustment for age, gender, tumour stage and tumour site, significant improvements in the relative risk of death were observed between the periods of 1995-2000 and 1980-1989 for patients under 60 years of age (Relative Risk (RR)=0.45; 95% Confidence Interval (CI)=0.35-0.58) and those 60-74 years old (RR=0.62; 95% CI 0.53-0.72). No improvement in the risk of death was found for patients aged 75 years and over. No improvements in the distribution of tumour stage were observed, making it very likely that the continuing increase in population-based survival among patients aged <75 years results from the shift from postoperative to preoperative radiotherapy, the development of the total mesorectal excision technique and the related tendency to subspecialisation of surgeons in colorectal cancer surgery.