Sacral agenesis is a rare congenital abnormality of the lower vertebral column which is fequently associated with neurological, orthopedic as well as urological malformations. With regard to the incidence of the anomaly, although approximately 200 cases have been reported previously, the occurrence of sacral agenesis in siblings has only rarely been found. To date only two pairs of siblings have been reported. Herein we present 2 siblings with partial sacral agenesis and emphasize the need for a careful family investigation, early diagnosis and appropriate treatment.