A 55-year-old woman was referred to our hospital with dysuria. We were unable to catheterize her using a nelaton catheter because of a urethral stricture, resulting in a large residual urine volume on ultrasonography. The circumference of the periurethral tissue was also thickened and the entire length of the urethra was stenotic, without apparent cause, on magnetic resonance imaging. Biopsy did not reveal malignancy. The pathological diagnosis of the periurethral tissue was simply fibrosis, and there was no definitive diagnosis. We decided to place a guidewire to attempt transurethral dilation, but it was unsuccessful because of the urethral stricture. The patient then underwent Mitrofanoff appendicovesicostomy. Three years later, there was no difficulty with catheterization through the appendix, despite her suffering from a bladder stone during the interim. We consider the Mitrofanoff appendicovesicostomy a good substitute technique for catheterization in patients with very severe urethral stricture.