Surgical site infection (SSI) rates vary from 1% to 5% in the month following surgery. Due to the large number of surgical procedures conducted annually, the costs of these SSIs can be considerable in financial and social terms. Many interventions are used with the aim of reducing the risk of SSI in people undergoing surgery. These interventions can be broadly delivered at three stages: preoperatively, intraoperatively and postoperatively. The intraoperative interventions are largely focused on decontamination of skin using soap and antiseptics; the use of barriers to prevent movement of micro-organisms into incisions; and optimising the patient's own bodily functions to promote best recovery. Both decontamination and barrier methods can be aimed at people undergoing surgery and operating staff. Other interventions focused on SSI prevention may be aimed at the surgical environment and include methods of theatre cleansing and approaches to managing theatre traffic.