Gastrocystoplasty is a form of surgical bladder augmentation or neobladder used to restore bladder capacity and compliance in children and in patients with neurogenic bladder. Other forms of bladder augmentation include ileocystoplasty and colocystoplasty. Reported complications of gastrocystoplasty include post-operative bleeding, haematuria, stricture, metabolic alkalosis and rupture of the gastric segment. There are reports of adenocarcinomas arising in the setting of ileocystoplasty and colocystoplasty. However, the first case of adenocarcinoma arising in the setting of a gastrocystoplasty is reported.