Background Cisplatin (CPN) is used in the treatment of various cancers. However, the especially nephrotoxic effect is limiting its use. We aimed to evaluate the renoprotective effects of Irbesartan (IBN) on CPN-induced acute kidney injury via mitochondrial stress related apoptosis. Methods and Results 32 rats were divided into 4 groups as control, CPN, CPN + IBN and IBN. Water or IBN 50 mg/kg (orally) was administered for 7 days and a single dose of CPN (5 mg/kg) intraperitoneally was given CPN and CPN + IBN groups on fourth day of experiment. At the end of the experiment, serum BUN and creatinine (Cre) levels, which are the indicators of kidney function are measured. Bcl-2-associated X protein (Bax) and B-cell-lymphoma-2 (Bcl-2) mRNA levels were analyzed by using qRT-PCR from kidneys as a mitochondrial stress indicator. Also, active caspase-3(cas-3) protein and tumor necrosis factor alpha (TNF-alpha) expressions were examined by immunostaining of the kidney tissues. For evaluation of oxidative stress, malondialdehyde (MDA), total oxidant status (TOS) and total antioxidant status (TAS) levels of renal tissues were measured and oxidative stress index (OSI) were calculated. CPN increased serum BUN and creatinine levels. Also, MDA, TOS and OSI levels were significantly elevated and TAS levels decreased in the CPN group. Moreover, CPN elevated the levels of Bax, active cas-3 protein and TNF-alpha expressions and suppressed Bcl-2 levels. IBN treatment reversed all these changes. Conclusions IBN significantly regressed kidney damage by its anti-inflammatory and antioxidant activity via inhibiting mitochondrial stress. IBN could be used as a renoprotective agent in CPN-induced kidney injury.