Abstract: The advantage of completely closing the pericardium after a coronary artery bypass grafting is the avoidance of injury of the heart and grafts during a re-operation. However, it would obviously be counterproductive to close the pericardium with a substitute that is predisposed to infection. This study was designed to evaluate the safety of ePTFE surgical membrane in comparison to native pericardium or autologous tissue. Between January 1992 to March 2003, 695 coronary artery bypass graftings were performed. The hearts and grafts were covered with ePTFE surgical membrane (474 cases: ePTFE group), or autologous pericardium and/or other autologous tissue (221 cases: non-ePTFE group). Often, a bilateral dissection of the internal thoracic artery was performed, which lengthened the surgery, the cardiopulmonary bypass, and the aortic clamp, in the ePTFE group. But there was no difference between the ePTFE group (2.1%) and the non-ePTFE group (3.2%) in the development of postoperative mediastinitis. There was also no difference between the two groups in the organism type of the infection. Methicillin resistant Staphylococcus aureus (MRSA) is the most common organism cultured from sternal wound infections; there were five cases in the ePTFE group, and four cases in the non-ePTFE group. In the ePTFE group, the hospital mortality due to postoperative mediastinitis was zero, and there was also no significant difference between the ePTFE group and the non-ePTFE group in time from the drainage operation to discharge; 74.3 days in the ePTFE group, and 81.0 days in the non-ePTFE group. The clinical use of ePTFE surgical membrane for a coronary artery bypass grafting does not appear to be a risk factor for mediasitinitis.