Purpose: Cancer following augmentation cystoplasty is a recognized risk factor. The procedure has only gained popularity in pediatric urology within the last 25 years, limiting the population being studied by statistical power and the lack of long-term followup. The majority of reported cases of post-augmentation malignancy have occurred in adults with multiple risk factors. Currently the most common indication for augmentation cystoplasty in children and adolescents is neuropathic bladder. We review 3 cases of transitional cell carcinoma (TCC) following augmentation cystoplasty in this unique population with no additional risk factors for bladder cancer. Materials and Methods: We reviewed our clinical database of children and adolescents who underwent bladder augmentation since 1978 to evaluate the incidence of cancer. This study represents a captured population within a single institutional practice. There were 483 cases entered into the database, and particular attention was paid to 260 augmentations with at least 10 years of followup. We reviewed medical history, clinical outcomes, cancer risk factors, augmentation type and pathology of the 3 patients who presented with TCC after augmentation cystoplasty. Results: Three patients presented with grade 2 to 3 TCC following bladder augmentation, all of whom underwent exploratory laparotomy and eventually died of metastatic disease. No patient had a history of smoking exposure greater than 10 packs per year or other known risk factors for bladder cancer. Two patients had an ileocecal augmentation and 1 had a cecal augmentation for neuropathic bladder. Patient age at augmentation was 8, 20 and 24 years, and age at diagnosis of TCC was 29, 37 and 44 years, respectively. Mean time from augmentation to TCC was 19 years. Assuming a 10-year lag period before the risk of cancer, in at least 1.2% of bladder augmentation cases in our database cancer has developed. Conclusions: This study supports the hypothesis that bladder augmentation appears to be an independent risk factor for TCC, with a lag time of less than 20 years. We recommend endoscopic surveillance of all patients with a history of bladder augmentation beginning 10 years after initial surgery.