ABSTRACT: In cases of trauma to the left renal vein (LRV), its ligation near the inferior vena cava (IVC) is considered, but the consequences are not always good. We investigated the role of collateral venous drainage after ligation of the LRV by studying the renal function and histology after ligation of the LRV near the IVC alone or with ligation of the gonadal or adrenal collaterals, in right-nephrectomized (RN) rats. Ligation of the LRV near the IVC alone (group 1) or with ligation of the adrenal (group 2) or gonadal (group 3) collaterals was studied in RN Wistar rats (n=18 per group). The renal histopathology (ischemic cortical necrosis) and functional status (urea, creatinine, sodium, and potassium) were compared. In RN rats, the results were better when ligating the LRV near the IVC alone or with the adrenal collaterals [mortality 4/18 (22.2%) and 3/18 (16.7%), respectively] than when ligating the LRV near the IVC plus the gonadal collaterals [mortality 15/18 (83.3%)] (p