A fistula between the renal pelvis and duodenum (pyeloduodenal fistula) is very rare. It can occur spontaneously or after trauma to one of these organs. A spontaneous pyeloduodenal fistula is usually caused by chronic inflammation, including reactions to foreign bodies, nephrolithiasis, benign and malignant neoplasms, as well as pyogenic infections. The main treatment to date has been surgery. We encountered one case of pyeloduodenal fistula found during an evaluation for abdominal discomfort in a 39-year-old female. Pyeloduodenal fistula was diagnosed by upper gastrointestinal endoscopy and abdominal computed tomography, and it was caused by direct invasion of nephrolithiasis. Surgical operation was recommended, but the patient refused. The patient has been free of symptoms for four years. Herein, we report an unusual case of pyeloduodenal fistula without surgical management and relevant literature review. (Korean J Gastroenterol 2018;71:229-233)