Craniolacunia (lacunar skull, Luckenschadel) is characterized by multiple, round or oval, radiolucent defects, sharply separated by dense strip of bone (honey comb like configuration) which tend to cluster in the cranial vault on plain skull film. Craniolacunia is present at birth and frequently associated with myelomeningocele, encephalocele or other congenital abnormalities of the central nervous system. Patients with carniolacunia have high mortality due to these associated lesions, and to the secondary effects of these neurological lesions. Recently, it is interested that the presence of carniolacunia can be used as an early indicator of intellectual capacity or recommendation of early indicator of intellectual capacity or recommendation of early surgery for associated lesions. Two cases of craniolacunia with meningocele in the lumbar region and encephalocele in the frontal region are presented and the etiology, clinical significance, prognosis of craniolacunia are discussed. Case 1 (Fig. 1, 2, 3), who had a soft tumor in the lumbar region since birth, was admitted to Saiseikai Yahata Hospital under the diagnosis of meningocele on October 26, 1973. The circumference of the head was 32.5 cm, and the lumbar tumor was infant fist growth, oval, brownish and soft in appearance. The patient had no neurological positive signs or other abnormalities including chest, abdomen and extremities. Plain skull film showed typical craniolacunia in the parietal, frontal and occipital region of the vault. Three days after admission, the patient had opisthotonus like posture at times and convulsive seizure of extremities. Suspected of meningitis, ventricle tap was performed. From the findings of obtained cloud xanthchromic cerebrospinal fluid which was revealed pleocytosis and many Klebsiella or other Gram (-) bacilli on bacterial culture, the diagnosis of ventriculitis was made...