Tuberculous arthritis on the sternoclavicular joint is an uncommon disease and a delayed diagnosis can be due to the obscure clinical symptoms. We should suspect tuberculous arthritis in patients with slowly progressive pain, swelling, mild fever and a previous history of tuberculosis. Early diagnosis is important through conducting a thorough physical examination and performing laboratory tests and radiologic study. Tuberculous arthritis on the sternoclavicular joint should be treated with a combination of systemic antituberculous agents and thorough surgical debridement in marked damaged joints. When performing this operation, it is important not only to minimized the injury of the costoclavicular ligament, but also to avoid injury to the surrounding the vital structures such as the mediastinum and pleura after aggressive resection or radical debridement. We describe here 2 cases of the tuberculous arthritis on the sternoclavicular joint: one case had a good result after surgical debridement with using an anti-tuberculous agent, and the other had fatal complications such as mediastinal abscess and pleural effusion after the operation.