Purpose: Surgical site infection following colorectal surgery is a frequent and costly problem. Barrier protection at the time of this form of surgery has been used with varying results. The aim of this randomized study was to examine the efficacy of barrier retractional wound protection in the prevention of surgical site infections in open, elective colorectal surgery. Methods: One hundred thirty consecutive patients undergoing open elective colorectal resectional surgery were randomly assigned to have either barrier retractional wound protection or standard wound retraction. Patients were then followed up for a minimum of 30 days postoperatively. The primary end point was surgical site infection as defined by the Centers for Disease Control and Prevention. The secondary end point was performance of the wound protector as assessed by operating surgeons. Results: There was a significant reduction in the incidence of incisional surgical site infections when the wound protector was used: 3 of 64 (4.7%) vs 15 of 66 (22.7%); P = .004. Most surgical site infections were diagnosed after discharge from the hospital (78%), and there was no difference in the rates of reoperation, readmission, or formal wound drainage between the 2 groups. Surgeons found the wound protector to be helpful with retraction during surgery, with 88% (7/8) adopting it as part of their standard setup. Conclusions: In this study the use of barrier wound protection in elective open colorectal resectional surgery resulted in a clinically significant reduction in incisional surgical site infections. Barrier wound protection of this nature should be considered routine in this type of surgery.