Anterior sacral meningomyelocele is the rarest and least known form of congenital myelocele. It is not manifested externally, it is usually not attended with changes in the neurologic status, and may be regarded as a presacral dermoid cyst. The authors observed 5 members of one family with similar clinical and X-ray signs of such herniations, in 2 they were verified. The presence of cystic structures in the cavity of the small pelvis in conjunction with a congenital defect in the bodies of the sacral vertebrae is an indication for conducting pneumomyelography so as to make a more precise diagnosis. A study of the hereditary and family history is a necessary trend in the examination of such patients because the disease may be of a familial character.