Retroaortic left renal vein (RLRV) is a relatively rare congenital anomaly of renal vasculature. The possible clinical symptoms of this type of vascular varition include hematuria, abdominal or flank pain. The urological symptoms are due to the increased pressure of the left renal vein, which is secondary to posterior nutcracker syndrome. RLRV can be diagnosed by doppler ultrasound, computed tomography or magnetic resonance imaging. Although the incidence is low, the diagnosis of this variant is particularly important for surgical implications. Abnormal renal vein can be a significant impact on surgeon, failure to diagnose these anomalies can lead to vascular injury and major bleeding. This report analyzes two clinical cases of incidental finding RLRV in a kidney donor and reviews the literature regarding embryological development, pathogenesis, treatment, and surgical implications for this renal vein variation.