Isolated involvement of the sternum is rare, representing less than 1% of tuberculous osteomyelitis. In this report, a 51-years-old woman who was admitted to the hospital with a localized solid mass in the sternum has been presented. A soft, painful mass measuring 3 cm in diameter in the lower sternum was detected during physical examination. Radiological investigation revealed presternal soft tissue and bone expansion in the posterior side of lower sternum. The patient was treated with non-specific antibiotics for a suspected diagnosis of osteomyelitis but the lesion did not show any regression. Since the microbiological analysis of fine needle aspiration fluid demonstrated acid-fast bacilli in direct microscopy and Mycobocterium tuberculosis was isolated from the culture, anti-tuberculous therapy consisting of isoniazid (INH), rifampicin (RIF), pyrazinamide (PZA), and ethambutol (ETM) was started. Sputum and urine cultures of the patient yielded negative results in terms of tuberculosis. After the first month of the therapy, her skin lesion was completely healed. Since the strain was found to be resistant to isoniazid, the maintenance therapy has been applied as INH + RIF + PZA for nine months. The history of the patient indicated that one of her relatives had skin tuberculosis on the face. As a result the patient has been successfully treated with anti-tuberculosis combination therapy together with surgical debridement.