The incidence of wound inflammation and infection for ten days after routine cardiothoracic operations was monitored in 454 patients having routine open-heart surgery (179), thoracotomy (100), or coronary artery bypass surgery (175). The percentage incidence of inflammation/infection for intracardiac operations was 12/2.3, for thoracotomies 12/1, and for coronary artery surgery including leg wounds 39/12 (sternal infection rate 7.5%). The incidence of staphylococcal infection was similar in the three groups. The excess of sternal wound infections in patients having coronary artery surgery was related to gram-negative bacteria (enterobacteria or acinetobacter) and similar bacteria were found in leg wounds. The findings suggest that bacteria from the leg or perineum are transmitted to the sternal wound at operation. A preoperative bath with chlorhexidine did not alter the incidence of infection but did seem to reduce the incidence of inflammation in leg wounds.