We report the case of a six-week-old baby who underwent irradiation for a giant hepatic hemangioma. After medical treatment including corticosteroids and interferon, no response was observed. She progressed to respiratory failure, requiring the use of mechanical ventilation. An emergency radiation therapy of the liver was decided. We observed a rapid improvement of the child, with the recovery of autonomous breathing without mechanical ventilation and a normalization of cardiac functions. Two months later, a partial left hepatic embolization was needed due to a progression of a localized blood flow. Six months later, she finally came back home. Cardiac output was normal and hepatomegaly began to regress. One year later, ponderal status is satisfactory, and it remains a localized hepatic right lobe hypertrophy without functional consequence.