Although cystitis glandularis has been considered a premalignant lesion, the instance of cystitis glandularis progression to adenocarcinoma or cystitis glandularis associated with adenocarcinomatous change is rare. This article includes 4 cases of neurogenic bladder with urinary diversion for different periods of time. In the first case with ureterocutaneostomy for twenty-five years diffuse cystitis glandularis with multifocal adneocarcinomatous change developed. The second case with suprapubic cystostomy for twenty-two years had diffuse cystitis glandularis of gastrointestinal type without evidence of malignancy. The other 2 cases with suprapubic cystostomy for merely ten years showed only mild to moderate cystitis glandularis and chronic cystitis with squamous metaplasia, respectively. The extent of cystitis glandularis appeared to correlate with the duration of urinary stasis. Ureterocutaneostomy rendered constant infection of the urinary bladder of the first case because of inadequate drainage. Thus, we assume that the intensity of the infection with a toxic product and virulence of organism may be responsible for the development of adenocarcinoma in this patient. Cystitis glandularis, especially diffuse type, can undergo malignant degeneration under constant irritation, but it is a long-term process.