Humeral nonunions still present a challenge to the orthopedic surgeon. Many methods of treating recalcitrant, posttraumatic humeral shaft nonunions have been described, with varying degrees of success. The present report reviews our experience with the use of vascularized fibular grafting for the treatment of large humeral defects. We treated 13 patients, with an average length of the humeral defect of 10.5 cm. Nine patients healed primarily, 3 required additional bone grafting, and 1 had a second fibular transplant. The mean period to radiographic bone union was 6 months. Only 5 patients regained full range of motion of the shoulder and elbow. The vascularized fibular graft is a reliable reconstructive procedure for recalcitrant pseudoarthrosis of the humerus in which the bony gap is greater than 6 to 7 cm, especially when traditional procedures have not provided the expected result.