Arterial wall infections are rare after orthotopic heart transplantation. An infected pseudoaneurysm developed in a patient at the site of aortic cannulation 6 months after his transplant procedure. Debridement of the infected tissue necessitated removal of a major portion of the aortic arch and reconstruction with in situ placement of a synthetic polyester (Dacron) graft. In situ placement of grafts is a controversial form of treatment of arterial wall infections in other portions of the aorta. Because of the extensive nature of the infection and its site, no other option was available. This patient represents the first reported case of successful aortic arch replacement for an infected pseudoaneurysm after orthotopic heart transplantation.