Staphylococcus aureus (S aureus) is the major cause of surgical site infections (SSI). At The Christ Hospital, Cincinnati, OH, S aureus accounted for over 80% of sternal wound infections in cardiac surgery patients. Approximately 700 cardiac surgeries are performed each year, with an associated infection rate of 1.8% per 100 procedures performed. In an attempt to reduce S aureus sternal wound infections, the use of prophylactic intranasal mupirocin was examined.