The authors describe three anatomic variations, circumaortic, retroaortic left renal vein, and retropelvic tributary of the renal vein, in Japanese cadavers. The incidences and the clinical significances of these variations are discussed with a detailed review of the literature. The median incidences of circumaortic left renal vein (CLRV) were 7.0% in cadavers examined and 1.8% in clinical subjects examined. The detection of CLRV in CT/MDCT or angiography was relatively difficult compared with that by cadaver dissection. The median incidences of retroaortic left renal vein (RLRV) were 1.7% in cadavers examined and 2.2% in clinical subjects examined. The detection of RLRV was lower in operations, and relatively easy by ultrasonography. The incidence of retropelvic tributary of the renal vein ranged from 30.0 to 46.4%, which is very frequent. Moreover, the incidences of communicating veins between the left renal vein and retroperitoneal veins ranged from 30.0 to 84.2% in cadaver dissections and from 34.0 to 75.8% in clinical reports.