Between 1975 and 1981, late infection of the prosthesis developed in 4 out of 207 patients (1.9%) who had prosthetic grafts placed in the chest or mediastinum. Organisms were Staphylococcus epidermidis (2 patients), Enterococcus, and Aspergillus. Infection occurred 4 to 57 months after initially clean operations for thoracoabdominal aneurysm, aortic angioplasty with valve replacement, ruptured postcoarctation aneurysm, and type A dissecting aortic aneurysm. All 4 patients were managed successfully and remain free from infection 11 to 42 months later. Based on this experience, several guidelines useful in the management of these infections have evolved: (1) prompt reoperation with complete debridement of infected and necrotic tissue, (2) removal of infected prosthetic material if suture lines are involved, (3) local antiseptic irrigation and appropriate, specific systemic antibiotics, (4) rerouting of blood flow through clean operative fields, and (5) use of pedicle flaps.