Bacillus Calmette-Guérin (BCG) vaccine has a good safety profile in immune competent children and considerable risks such as disseminated BCG disease in individuals with immune deficiencies. However, some complications including local subcutaneous infection, regional suppurative lymphadenitis may occur after BCG vaccination in immune competent children. A 17-month-old female child was admitted with a painless protruding mass on the anterior chest wall. There was no evidence of previous tuberculous infection and contact with a tuberculosis patient. Chest-computed tomography revealed an oval shaped low attenuated 1.8 x 1.0 cm mass at subcutaneous and muscle layers just below sternum, but the pulmonary parenchyma seemed to be normal. We excised the mass and the histopathologic examination revealed granulomatous lesions that suggestive of mycobacterial disease process. We considered that the chest wall abscess was a complication of BCG vaccination occurred by hematogenous dissemination of the inoculated mycobacteria. She recovered without any complications and was treated with isoniazid (150 mg/day) and rifampin (150 mg/day) for 6 months as an outpatient, not directly observed therapy but monthly follow-up.