BACKGROUND: Differences between men and women in complication rates after cardiac surgery have been reported. The rate of one of the most severe postoperative complications, sternal wound infection, has not been compared between the sexes. OBJECTIVE: To compare the frequencies of 21 risk factors for sternal wound infection between men and women. METHODS: Records of 306 patients who had cardiac surgery between 1989 and 1999 at 3 different hospitals in the southwestern and southeastern United States were reviewed for 21 risk factors. Of the 306 patients, 115 (25 women and 90 men) had experienced a sternal wound infection and 191 randomly selected patients (52 women and 139 men) had not. RESULTS: Three risk factors occurred at significantly different rates in men and women. Smoking and use of a single internal mammary artery for grafting were more common in men than women. Women were older than men at the time of cardiac surgery. Logistic regression analyses showed that the 3 dichotomous risk factors (use of single internal mammary artery for grafting, smoking, age > 70 years) that univariate analysis indicated were significantly related to sex could also be used to predict infection group. CONCLUSIONS: This study contributes to the awareness of the possible differences between men and women in the risk of sternal wound infection developing after cardiac surgery. Although 3 risk factors occurred at significantly different rates in men and women, further research is needed to determine the effects that these differences in risk factors may have on the occurrence of sternal wound infection in men and women.