Introduction: A 43-year-old man developed a mediastinal abscess after a redo aortic valve along with an ascending aorta replacement andalso a sub-aortic membrane resection. He was surgically revised: as there were no signs of involvement of the valve and vascular prosthesis,a pedunculated tract of the greater omentum was mobilized and positioned around the aortic prosthesis. During a 10-month follow-up,it has been revealed that the patient is doing well and has no recurrence of the infection. Use of the great omentum could be consideredin the selected mediastinitis cases. Case Presentation: A 43-year-old man was referred to our institution for a severe aortic regurgitation and an ascending aorta enlargementassociated with a relapsing sub-aortic membrane, which had been treated in his childhood. He underwent a redo ascending aortareplacement and an aortic valve replacement (mechanical prosthesis) along with a resection of the relapsing sub-valvular membrane.Some weeks after he was admitted to another hospital for fever, arthromyalgias and chest pain. After a few days, he developed aninflammatory jugular swelling and underwent a chest CT scan showing a bulky anterior mediastinal abscess in the direct continuity withthe sternum. A further chest CT scan showed a mediastinal para-aortic capsulated mass, 135 × 85 × 90 mm in dimension, well delimitedover the surrounding plans. At the top of the lesion, a further fluid collection was appreciated, extending through the sternum over thesubcutaneous tissues, 30 × 20 mm in dimension. Re-sternotomy was performed and the mediastinal mass was opened and drained.After an extension of the median sternotomy through the epigastrium, a pedunculated tract of the greater omentum was mobilized andpositioned around the vascular prosthesis to fill the empty space left by the abscess. Conclusions: The greater omentum is well known in cardiothoracic surgery for its valuable features such as plasticity, immunecompetence, good blood supply and neovascularization-potential. Dead space can be obliterated by omental flap because of its plasticityqualities. It contains a large number of immunologically active cells likely to be responsible for its anti-infective properties. We can affirmthat use of the great omentum could be considered in selected post-operative mediastinitis cases after cardiac surgery.