A 21-year-old male presented for surgical management of a right-sided ureteropelvic junction obstruction. A dismembered pyeloplasty via a robotic-assisted laparoscopic approach was attempted, but the ureter could not be mobilized to perform a tension-free anastomosis. Ureteral reconstruction was necessary and use of small bowel was planned to replace the non-functional ureter. However, patient was noted to have a healthy and patent appendix, which was utilized in lieu of small bowel. The surgery was converted to an open procedure, and an appendiceal interposition was successfully performed. The patient’s immediate postoperative period was significant for a small urine leak, exacerbated by an episode of urinary retention, which was managed successfully with an indwelling urethral catheter and a ureteral stent. The rest of the patient’s postoperative course was uneventful, and he remains symptom-free at three-month follow-up. This case highlights the successful use of an appendiceal interposition for ureteral reconstruction in a patient who required a right-sided pyeloplasty for ureteropelvic junction obstruction.