PURPOSE: The purpose of this study was to evaluate the clinical results of the 4+5th extensor compartmental artery pedicled vascularized bone graft in advanced Lichtman stage III Kienbock's disease. MATERIALS AND METHODS: Eight patients with advanced Lichtman stage III Kienbock's disease who underwent the 4+5th extensor compartmental artery pedicled vascularized bone graft and followed up more than 1 year were analyzed retrospectively. There were 3 men and 5 women. The mean age was 43.6 years old. Two patients were Lichtman stage IIIA and six patients were IIIB. The clinical outcomes were evaluated with radiocarpal joint pain, range of motion, grip strength, carpal-height ratio, radioscaphoid angle, return to daily living activity and/or work. The mean follow up period was 38.5 months (range from 12 to 86 months). RESULTS: On last follow up, the pain was disappeared in 6 patients, and mild occasional pain was remained in 2 patients. Mean radiocarpal joint flexion and extension were 55 degrees and 60 degrees, 87% and 88% of the normal side, respectively. The carpal-height ratio was maintained or improved in 6 patients and slightly decreased in 2 patients. Radioscaphoid angle were improved or maintained in 7 patients. Mean grip strength was 67 lb, 93% of the normal side. All 8 patients returned to daily living activities and/or their previous works. CONCLUSION: The 4+5th extensor compartmental artery pedicled vascularized bone graft prevented the progression of disease and provided clinical improvement even in advanced Lichtman stage III Kienbock's disease.