An anterior sacral meningocele, a rare congenital anomaly, manifested in a previously healthy 44-year-old woman with findings of meningitis, including headache, vomiting, unconsciousness, and fever. Nontraumatic pneumocephalus, tetraventricular hydrocephalus, fluid-fluid level at the lateral ventricles, and pial enhancement were observed on multidetector computed tomography. A ventricular drainage catheter was placed to decompress the hydrocephalus, and drainage was performed urgently. Escherichia coli was isolated from the drainage material. Whole-spine magnetic resonance imaging and fistulography were undertaken on the third day after admission to evaluate for anal and urinary incontinence and pareses of both upper and lower extremities. Spinal arachnoiditis, tethered cord, dysgenesis of the sacrum, and a rectothecal fistula were demonstrated. Specific antibiotic treatment and surgery for fistula tract excision were performed.