We report a 15-year-old girl with nutcracker syndrome (NCP) in whom three-dimensional helical computed tomography (3D helical CT) was useful for diagnosis; angiographic imaging using 3D helical CT provided fine outlines of the vascular structures in NCP, i.e., a compression of the left renal vein between the aorta and the superior mesenteric artery and the abnormal acute angle between them. Thus, a 3D helical CT enables precise depiction of the anatomical characteristics of renal vasculature and, therefore, may be a useful alternative imaging technique instead of conventional examinations, such as invasive venography or digital subtraction angiography. Further study in a large number of children with vascular abnormalities would be worthwhile.