Introduction: Serious complications following vaccination with BCG are rare. Among these complications, osteitis is of particular interest because it is more common and appears to occur in immune competent patients. Despite the diagnostic criteria proposed by Foucard and Hjelmsted in 1971, post-vaccination BCG osteitis is rarely recognized in pediatric practice, with only 25% of cases being diagnosed. Observation: We report the case of a 12-month-old infant, who presented to pediatric emergencies for partial functional impotence of the upper left limb, evolving for 2 months in a context of apyrexia and of conservation of the general state. The patient was vaccinated with BCG at day 15 of life. The injection site was the left deltoid. The dose and type of vaccine used was not specified. He had not had any local post-vaccination complications, nor recent trauma of the limb, and there was no known tuberculous contusion in the environment. Results: On examination, the infant had pain while the stretching the left arm, relieved by the limb against trunk position. The palpation had found a firm, painless, non-inflammatory mass of the anterior aspect of the upper third of the left arm. The radiograph of the left shoulder had revealed a lytic metaphyseal-diaphyseal left humeral image. MRI showed a lesion process of the upper extremity of the aggressive left humerus with invasion of neighboring structures. A bone biopsy performed had objectified granulomatous osteitis without caseous necrosis. The tuberculin IDR was phlyctenular, reaching 18 mm. The rest of the balance sheet looking for other locations was negative. Anti-bacillary triple therapy (rifampicin, pyrazinamide, isoniazid) was started. The evolution after 6 months of treatment remains favorable, with persistent apyrexia, preserved appetite, and weight gain of 3 kilograms. Conclusion: Osteitis after BCG vaccination is a rare, underestimated and difficult to diagnose. It should be considered in small children who have already received BCG vaccination, have had no contact with tubercolosis and have clinical findings consistent with osteitis, but do not respond to conventional antibiotics. It has a better prognosis, with a good response to anti-bacillary and surgical treatment. Clinical trials are needed to codify therapeutic management.