Anterior sacral meningocele (ASM) is a rare congenital malformation. Often while still asymptomatic, ASM may achieve a considerably size, to the extent of exerting a mass effect on the pelvic structures. Spontaneous rupture with subsequent septic meningitis is the most frequent and dangerous complication. The meningocelic sac is usually isolated by a surgical procedure that requires a sacral laminectomy or a transabdominal approach. Recently an alternative surgical technique, the posterior sagittal approach, has been proposed. We report on a 15-year-old girl with a long clinical history of constipation and sporadic cystitis. Radiological examinations showed progressive enlargement of a presacral lipomeningocele, which grew to 12x14 cm. A posterior sagittal approach was performed; the stalk was ligated, the sac totally excised and a small associated tumour removed. No intra-/post-operative complications were observed. The posterior sagittal approach is an easy and safe surgical technique for the treatment of ASM, as it allows a complete isolation of the lesion and the removal of associated tumors without significant morbidity.