PURPOSE: Just more than 20 years ago a group of associated findings was identified in patients with posterior urethral valves and persistent upper tract dilatation following valve ablation, including a noncompliant thick walled bladder, incontinence and nephrogenic diabetes insipidus. Subsequently the pseudonym "valve bladder syndrome" became associated with this phenomenon. The history of the valve bladder syndrome concept, continuing debate regarding the etiology and management of the valve bladder, and 20 years of urodynamic and histological investigations are reviewed. MATERIALS AND METHODS: Outcome studies, histological findings, animal model experimentation and urodynamic investigations reported in the literature more than the last 20 years were reviewed and compared. RESULTS: Varying degrees of bladder compliance loss are seen in the majority of patients following valve ablation. Severe loss of compliance can lead to persistent upper tract dilatation and later urinary incontinence. A large urine output, secondary to a loss of renal concentrating ability, contributes to the persistent dilatation and incontinence. Correcting bladder compliance loss helps to lessen the dilatation and incontinence. A literature review revealed little to support the belief that previous temporary diversion is the major cause of severe compliance loss. In fact, instances of severe compliance loss were seen following any mode of therapy, including valve ablation alone, and likely represents a persistent finding secondary to the degree of damage incurred in utero. That there are more patients requiring augmentation after temporary diversion should not imply that diversion caused the poor compliance but that an initially poorly compliant bladder lead to diversion as the choice of treatment. Some investigators have found that many temporarily diverted cases have a bladder equal to or even better in function and capacity than those treated with valve ablation alone. Others have made a case but less substantially to conclude that diversion is the most significant cause of a small, poorly compliant bladder. CONCLUSIONS: Valve ablation alone without urodynamic followup is inappropriate. Proactive management must have a significant role. The vast majority of temporarily diverted cases do not result in a fibrotic, noncompliant bladder. Surgeons who strongly favor diversion should be comfortable with such an approach, although in most cases if diversion is considered, those same patients often can be treated just as adequately with proactive urodynamics and anticholinergic therapy without the required surgery for undiversion. With great anticipation, we look forward to studies that will determine if growth factor inhibitors or angiotensin converting enzyme inhibitors will have a role in preventing or reversing the histological changes of the valve bladder.