No standard treatment for Bacille Calmette-Guérin (BCG)-associated osteomyelitis, a rare but serious complication of the BCG vaccine, has been established. This study explored the short- and long-term outcomes of surgical intervention for BCG-associated osteomyelitis. Four patients with BCG osteomyelitis aged 9-21 months when diagnosed and treated at the Department of Orthopedics, Kaohsiung Veterans General Hospital, Taiwan, between January 2001 and April 2019 were analysed. Radiography revealed osteolytic lesions of the involved sites. Magnetic resonance imaging revealed physeal involvement in three patients. Debridement was performed for all four patients. One patient then underwent additional arthroscopy because of suspect intra-articular involvement. Specimens obtained intraoperatively were sent for pathology, culture, and to the national reference mycobacterial laboratory for BCG detection using polymerase chain reaction. All four patients had positive results for Mycobacterium bovis and satisfactory short-term results. Functional monitoring using QuickDASH or the Lower Extremity Functional Scale revealed excellent long-term outcomes despite tiny limb length discrepancy observed during follow-up in two patients. Prompt diagnosis plus proper intervention is required to prevent further major complications of BCG osteomyelitis. Minimally invasive debridement led to positive clinical outcomes and is therefore recommended.