The greater omentum, an original visceral flap, offers great possibilities of repair of complex defects. First proposed in the 1960s following the work by Kiricuta, rejuvenated following a better understanding of its physiology as a result of recent research, the value of the omentum resides in its specific properties of defence, detersion, and revascularization. During laparotomy, the only way of determining the extent of this organ (an average of 400 cm2) and defining its blood supply, the surgeon may decide to perform a flap on the left or right gastro-omental pedicle. The right pedicle is dominant with an artery and a vein which have a mean calibre of 2 millimeters. After colo-omental detachment and release of the greater curvature, the omentum pedicle flap reaches the entire anterior surface of the trunk, the proximal part of the limbs, and the base of the neck. It can be used as a free graft, or may be revascularised by microsurgery. It can be transferred to any site, especially to the proximal part of the lower limb. An immediate or secondary split-skin graft ensures cover of the organ. The indications for omentoplasty are eclectic, but restricted in relation to the initial proposals: it should no longer be used to reconstruct a relief nor to dry up bony suppuration, or to drain lymphoedema. The situations in which omentum still remains indicated, or even irreplaceable, are those in which a free or local flap is impossible, insufficient, or uncertain: poorly defined, deep, torpid, infected defects and cases of radiation necrosis, pharyngostomy, thoracic empyema (especially those maintained by a bronchial fistula). In cancers of the oropharynx, the addition of a conjoint potion of the stomach allows reconstruction of gastrointestinal continuity. In traumatology, an omental free flap can save a leg or a foot, with bony disruption and major soft tissue destruction. The only limitation to the use of the greater omentum is the laparotomy, which cannot always be performed in patients with respiratory failure or following multiple abdominal operations. Apart from this reservation, the omentum remains an "extreme" flap for "extreme" situations.