Over a 2-year period, 31 patients underwent prolonged hydrostatic bladder distension for benign and malignant bladder disease in this unit. Of these, 29 patients had benign functional disorders or bladder contracture, and in 2 patients hydrodistension was performed for complications of treatment for bladder neoplasia. Of the 29 patients with benign disease, 6 observed marked improvement and 8 some improvement in their symptoms, and 12 received no benefit. Patients with detrusor hypersensitivity fared better than those with detrusor instability or interstitial cystitis. A patient with malignant bladder disease died soon after the procedure as a result of a myocardial infarction. Problems attributed to the hydrostatic balloon catheter were responsible for 2 failures. The regional anaesthetic technique failed to provide adequate anaesthesia for hydrodistension in 9 procedures and limited the duration to 2 h in 13 others. Following recall of the perished balloon catheters by the manufacturer, and the introduction of continuous spinal anaesthesia, the number of technical failures has been reduced. This technique still has an important role to play in the relief of severe symptoms unresponsive to medical treatment, but it is important that ideal conditions are provided for hydrodistension in order to ensure maximum success, particularly when the alternative is major surgery.