Increasingly, children with ventriculoperitoneal shunts are undergoing urinary tract reconstructive surgery with bowel. The peritoneal end of the ventriculoperitoneal shunt tubing usually is exposed during the procedure, making the system vulnerable to infections and malfunction. The records of 103 myelomeningocele children with ventriculoperitoneal shunts and bowel-bladder reconstructive surgical procedures (27) were reviewed for evidence of an abdominal cerebrospinal fluid pseudocyst (6). Pseudocyst formation occurred in only 1 of 76 ventriculoperitoneal shunt patients (1.3%) who had not undergone versus 6 of 27 (22%) who had undergone an intra-abdominal procedure. The 6 children had a total of 8 pseudocysts, including 7 pseudocysts that developed 8 days to 47 months (average 15.1 months) after the reconstructive surgery and 1 that developed before reconstructive surgery. All patients had abdominal symptoms (pain or mass) or symptoms of increased intracranial pressure. Treatment included computerized tomography-guided needle aspiration or abdominal exploration with cyst evacuation and shunt repositioning or replacement. The walls of the pseudocyst were formed by matted loops of bowel. Additional shunt surgery was required in 5 patients with conversion to ventriculoatrial shunts. We conclude that the development of an abdominal cerebrospinal fluid pseudocyst is at least in part related to the prior abdominal surgery. Thus, pediatric urological and general surgeons caring for children with ventriculoperitoneal shunts should be aware of this complication.