Objective To explore a surgical method for chronic osteomyel itis of sternum after thoracotomy. Methods From January 2006 to February 2009, 11 cases of chronic osteomyelitis after thoracotomy (2 cases of coronary bypass, 6 cases of mitral valve replacement, and 3 cases of ventricular defect repair) were admitted. Of them, there were 6 males and 5females, aged from 6 to 62 years (median 34 years), including 6 cases of simple osteomyelitis of sternum, 2 cases of osteomyelitis of sternum with suppurative infection of mediastinum, and 3 cases osteomyel itis of sternum with costal chondritis. Necrotic sternum were excised and defect was from 4 cm × 3 cm to 7 cm × 4 cm. Greater pectoral muscle flap was designed from 8 cm × 5 cm to 10 cm × 6 cm on one side and was transferred to defect. Negative drainage and sensitive antibiotics were administered after operation. Results Healing by first intention was achieved in 10 patients except 1 patient who had a few discharge at the drainage outlet and whose incision healed 1 week later. The follow up was from 3 to 10 months with an average of 6 months. The formed scars were flat with soft texture in 8 patients and moderately hypertrophy in 3 patients. The wounds healed without pain, relapse or abnormal function of donor upper limb. Conclusion Transplantation of greater pectoral muscle flap is an effective way to repair chronic osteomyelitis of sternum after thoracotomy.