A 16-year-old adolescent boy was referred to our department because of severe macrohematuria and anemia. Physical examination revealed a left varicocele (Figure 1, white arrowheads). Urinalysis revealed orthostatic proteinuria with numerous isomorphic red blood cells in the urinary sediment. Abdominal computed tomography scan identified compression of the left renal vein between the superior mesenteric artery and the aorta (Figure 2, black arrow), and dilated spermatic vein (Figure 2, black arrowhead). Cystoscopy revealed macrohematuria only from the left ureteral orifice. The patient was diagnosed as having the nutcracker phenomenon and no treatment had begun. After 6 months, the patient’s hematuria and anemia spontaneously improved.