The main endpoint of studies evaluating antimicrobial prophylaxis in surgical patients is wound morbidity. This should consist of more than the solitary declaration of the rate of wound infection. In this study, a modified version of ASEPSIS (a wound scoring system) has been prospectively evaluated in 1000 patients undergoing cardiac surgery. Twenty-one patients (2.1%) had an infected sternal wound. The components of ASEPSIS most significantly associated with a sternal wound infection were: the presence of a purulent exudate, a postoperative stay > 14 days, the identification of pathogenic organisms, and the use of antibiotics (P <0.0001). Although ASEPSIS is a useful mechanism for conveying information about wounds, it does ignore bleeding into wounds and the extent that troublesome wounds need to be dressed after surgery.