A 15-year-old girl from Iraq presented with a swelling on her left chest wall without signs of infection. Surgical drainage and resection of the involved left 3rd costal cartilage was performed, which revealed tuberculous osteomyelitis. Tuberculosis is a public health problem in developing countries and can present as a cold abscess of the chest wall that is difficult to diagnose without biopsy. Drainage and debridement provide treatment while postoperative antibiotic therapy combined with surgery can prevent complications and recurrence.