Ewing sarcomas are the second most common primary malignant bone tumors in childhood and adolescence which rapidly metastasize. Due to improvement of treatment options in recent years, the survival rate has significantly increased. Nevertheless, lethality is still high, and neurologic symptoms are frequent. To the best of our knowledge, this is the first reported case of a sacral osteoneogenesis after complete sacrectomy in a patient with Ewing sarcoma.