The nutcracker phenomenon refers to compression of the left renal vein between the aorta and the superior mesenteric artery, which leads to painless intermittent gross hematuria. An 11-year-old girl presented with a two-year history of recurrent painless hematuria. Physical examination and routine laboratory examinations were noncontributory. Renal ultrasonographic study, selective left renal angiography and retrograde left renal venography showed evidence of compression of the left renal vein where it crossed between the aorta and the superior mesenteric artery. A needle biopsy of the right kidney revealed no abnormal histologic change. These results led to a diagnosis of the nutcracker phenomenon; to the best of our knowledge, this may be the first case reported in Taiwan. Herein, we present our experience with this case and discuss the diagnostic options.