Spontaneous peripelvic extravasation of urine is an uncommon urologic condition. The symptoms of right side peripelvic extravasation sometimes mimic acute appendicitis. We present a 42-year-old male who visited our emergency department complaining of severe pain over his right lower abdomen, present for one day. Physical examination showed tenderness with rebounding pain over his right lower abdomen. Laboratory reports revealed leukocytosis but normal urinalysis. Spontaneous peripelvic extravasation of urine was diagnosed by contrast-enhanced computed tomography (CT) of the abdomen and post contrast- enhanced kidney-ureter-bladder x-ray (KUB). Ureteroscopic examination revealed an ureterovesical junction (UVJ) stone and ureterolithotripsy was performed. A double J ureteral stent was then put in place. When a patient complains of right lower abdominal pain, the rare situation of spontaneous extravasation of urine should be considered.