OBJECTIVE Multimodality treatment is the preferred strategy in the management of low rectal adenocarcinoma. Preoperative chemoradiation therapy (CRT) associated with radical surgery may result in significant tumor downstaging, local control of the disease and high rates of sphincter-saving operations. METHODS One hundred consecutive patients with advanced and resectable distal rectal cancer treated either by surgery alone or by preoperative chemoradiation followed by surgery were reviewed. Both groups were similar in tumor and patients characteristics. Treatment strategy was randomly selected. RESULTS Mean tumor size in Group 1 (surgery alone) was 6.1 cm and 3.3 cm in Group 2 (CRT). In Group 1 (surgery alone), nine patients had stage I (18%), 20 had stage II (40%) and 21 had stage III disease (42%). In Group 2 (CRT), 6 patients had stage 0 (12%), 21 had stage I (42%), 12 had stage II (24%) and 11 had stage III disease (22%). Furthermore, for each T (except for T0-1) the presence of lymph node (LN) metastasis was significantly more frequent in Group 1. In Group 2 (CRT), there was a mean reduction of 27% of the initial tumor size. This reduction was observed in 58% of patients in this group (CRT). Finally, sphincter-saving operations were more frequently performed in Group 2 (CRT) even though tumor differentiation and distance from the anal verge were similar in both groups. CONCLUSIONS Preoperative CRT followed by radical surgery is an effective treatment strategy for distal rectal cancer resulting in significant tumor size reduction and downstaging. Consequently, these effects may be responsible for higher rates of sphincter-saving operations performed in this subset of patients.