A 67-year-old woman presented with erythema and swelling over her left elbow. She felt pain during palpation of the olecranon, while the range of elbow motion was slightly reduced (02 in circle-302 in circle-1302 in circle). She had been treated conservatively elsewhere for 3 months with nonsteroidal anti-inflammatory drugs and splint immobilization. Radiographs and computed tomography showed an osteolytic area over the olecranon with cortex disruption. She underwent open biopsy of the olecranon, and the histologic features were compatible with tuberculosis. Erythrocyte sedimentation rate was elevated and she had a positive Mantoux test (14 mm). She mentioned no history of pulmonary disease and had a normal chest radiograph. She received antituberculous treatment (isoniazid, rifambin, and pyrazinamide) for 2 months without obvious improvement. She underwent surgical debridement of the olecranon while she continued antituberculous treatment for 12 months, discontinuing pyrazinamide after the third month. After the completion of antituberculous treatment, the patient was pain-free, without local signs of infection and with improved range of motion (02 in circle-202 in circle-1452 in circle). Early diagnosis and treatment of olecranon tuberculosis is of great value, and the prognosis is good when there is no spread in the elbow joint.