Augmentation cystoplasty operations using segments of gastrointestinal tract are often necessary in neurogenic low-compliance bladders. Patients are usually rehabilitated with an increase in storage volume and normalization of the reduced compliance. However, gut mucosa-related early and late complications are not very uncommon. Malignancy, although rare, is known to occur after enterocystoplasty, but only one such case has been reported for gastrocystoplasty, a single patient who developed urothelial carcinoma. We describe what we believe to be the first case of signet ring cell carcinoma developing after gastrocystoplasty.