In a prospective study of 1,009 adult patients undergoing elective cardiac surgery at The Johns Hopkins Hospital, we determined the association between a variety of preoperative and operative parameters and the risk of postoperative sternal- or mediastinal-wound infection. Of the parameters reflecting nutritional state, only one, reduced level of albumin in serum, was significantly associated with sternal- or mediastinal-wound infection by univariate analysis. The final multiple logistic regression analysis indicated that four variables were significant (P less than .05) independent predictors of sternal- or mediastinal-wound infection: obesity (relative odds = 3.8; 95% confidence limits = 1.9-7.5), diabetes mellitus (relative odds = 2.6; 95% confidence limits = 1.4-4.8), length of hospital stay before surgery greater than five days (relative odds = 2.0; 95% confidence limits = 1.2-3.5), and current cigarette smoking (relative odds = 1.8; 95% confidence limits = 1.1-3.1). Of these variables, perhaps only smoking will lend itself routinely to attempts at intervention.