Major tracheal reconstructive surgery requires a flap to reinforce the suture line and prevent erosion of contiguous large vessels. Omentoplasty, myoplasty, or flaps with a blood supply arising from the branches of the internal thoracic (IT) artery such as the ‘‘pericardial fat graft’’ 1,2 or the ‘‘thymus flap’’ 3 can be used. We describe the ‘‘thymopericardial fat flap’’ (TPF), which includes the IT pedicle, overlying mediastinal pleura, homolateral thymic lobe, and continuous pericardial fat tissue. In adulthood, the intrathoracic portion of the thymic lobes remains as fat and connective tissue lying on the anterosuperior pericardium. Usually, one major thymic branch per lobe comes from the IT artery. 3 The pericardial fat tissue extends up to the caudal portion of the thymus and down the cardiophrenic angles, with the blood supply arising from the IT arteries (Figure 1). During major tracheal reconstructive surgery, the right TPF is mobilized through a median sternotomy combined with a collar incision. Given the length, IT pedicle harvesting is mandatory to ensure the viability of the distal part of flap (pericardial fat tissue). The thyroid isthmus and both thymic lobes are divided medially, with preservation of the superior thymic veins. To expose the undersurface of the right half of the sternum, an externally positioned sternal retractor is used. The initial part of the IT pedicle, with its adjacent fat and parietal pleura, is dissected up to the posterior face of the first costal cartilage, with preservation of the internal thoracic vein at its junction with the innominate vein. The incision is extended along the IT pedicle, down to the sixth intercostal space. The pedicle is freed from the thoracic wall caudally. The intercostal arteries and accompanying veins are identified and divided between surgical clips. The IT pedicle is divided in the sixth intercostal space. The flap is then freed from the ascending aorta and pericardium. Finally, the anastomotic vessels from the pericardiophrenic and musculophrenic branches are divided using a transpleural approach (Figure 1), allowing ‘‘en bloc’’ mobilization of an approximately 20-cm-long 3 5-cm-wide well-vascularized flap (Figure E1).