A case of anterior meningocele arising through a thin fistulous tract in the intervertebral disk space of L5-S1 is described. This lesion was giant, and almost completely filled the abdominal and pelvic cavities. Furthermore, it was associated with two separate intracranial meningiomas, a pleuropericardial cyst, and numerous developmental malformations. Pathogenetic factors, clinical and radiological features, and surgical treatment are discussed.