Primary adenocarcinoma of the bladder accounts for less than 2% of all bladder cancers. There is no report of such a case in a defunctionalized bladder. All reported cases of carcinoma in defunctionalized bladders were either squamous cell, signet ring cell, or transitional cell carcinoma, detected within an average of 5 years after urinary diversion, and all have been associated with chronic inflammation of the bladder. We report on 2 cases of adenocarcinoma that developed in defunctionalized bladders 30 and 8 years after ileal loop diversion for prune belly syndrome and neurogenic bladder, respectively.