Altough the use of drains is common in clinical practice, its real role in the prophilaxis and therapy of postoperative complications is still not clear. In the literature we can find both supporters of drains, and many opponents who consider their use unnecessary and sometimes even dangerous. In fact, during new experimental and clinical studies, it was impossible to determine the usefulness of prophilactic abdominal drain, at least in the case of colo-rectal anastomosis, it has been demonstrated that use of drains limits the risks of an anastomotic leakage but, in some cases, the same drains could be the cause of some of the complications that should be avoided. Although there is a considerable theoretical and practical evidences in favour of drainage, the dispute about “to drain or not to drain” the peritoneal cavity after elective colo-rectal surgery remains open. This retrospective study made on 150 patients operated on elective surgery for rectal cancer demonstrates that prophilactic drain does not significantly influence the general rate of leakage (3.15% for group A and 5.45% for group B, p > 0.1); in two of the three fistulas in patients with drains, the drains have permitted the diagnosis, but have not permitted the reduction of the number of operations for fistulas.