Purpose: In the present paper, we report on a 34-year-old female with macroscopic hematuria due to a nontraumatic renal arteriopelvic fistula (APF). The patient initially presented at another hospital with asymptomatic macroscopic hematuria. Following abdominal ultrasonography, computed tomography (CT) and laboratory data, no abnormal findings were seen. Therefore, the patient was referred to Teine Keijinkai Hospital for a more precise evaluation of the urinary tract and vascular abnormality. Methods/Results: Endoscopically, there was bleeding from the right ureteral orifice, so the patient was admitted for further examination. No abnormal findings were seen on urinary cytology and following an intravenous pyelogram. A selective right lower polar renal arteriogram revealed arterial extravasation directly into the pelvis before the venous phase, so APF of the kidney was diagnosed. The patient had no history of urinary tract trauma, so the APF was thought to be idiopathic. After transcatheter arterial embolization (TAE) with a gelatine sponge, macroscopic and microscopic hematuria disappeared and a low-density area was seen in the middle pole of the right kidney in an abdominal CT scan 4 days after TAE. This was thought to be renal infarction due to TAE. Conclusions: After discharge, the patient had no further hematuria.