Nocardial sepsis occurred after aortic valve replacement in two patients. A septic suture aneurysm of the aortotomy was resected and the prosthesis exchanged in one of them. The other received conservative treatment for sternal osteomyelitis and local mediastinitis. Clinical cure was followed by relapse and death from cerebral infarction, and necropsy revealed a septic suture aneurysm of the aortotomy. Radical surgical revision seems to be necessary for lasting cure in such infections.