To evaluate the efficacy of intravesical oxybutynin chloride, 42 patients who were incontinent secondary to uninhibited detrusor contractions and had failed oral anticholinergic therapy were begun on intravesical oxybutynin chloride. Indications for intravesical therapy were detrusor hyperreflexia (N = 20), detrusor instability (N = 19), and bowel/bladder overactivity after augmentation cystoplasty (N = 3). A 5-mg tablet dissolved in 30 cc of sterile water was instilled into the bladder two to three times daily via clean self intermittent catheterization. With a mean follow-up of 18.4 months, no patient reported side effects as a result of the intravesical therapy. Nine patients (21%) dropped out of the study due to inability to tolerate the catheterization or difficulty retaining the solution in the bladder. Eighteen of the 33 patients (55%) who followed the protocol experienced elimination or significant improvement of their incontinence. The results of the current study confirm the safety and usefulness of intravesical oxybutynin in treating uninhibited detrusor contractions in a difficult patient population.