Two patients of chronic mediastinitis after cardiac surgery were treated by omental transfer. Their previous cardiac operations were open mitral commissurotomy and aortic valve replacement. They underwent radical surgical therapy for mediastinitis 8 to 9 years after the first cardiac surgery. In both cases, the infection resulted from Dacron felt on the ascending aorta. Under the cardiopulmonary bypass, the Dacron felt and infected tissue were resected. And omental transfer was done to prevent recurrent infection. The patients have been follwed up for 10 to 14 months. And they have no symptoms of their mediastinitis during these periods. From these experience, we consider that omental transfer is very helpful to treat infectious complications after cardiac surgery.