Introduction: Acute kidney injury (AKI) is a serious pathology that progress with dysfunction of regulating blood pressure and fluid balance, concentrating urine due to decrement of aquaporin-1 (AQP) levels during the inflammation process. Irbesartan (IRN), angiotensin receptor blocker, is widely used in the treatment of hypertension, which also has anti-inflammatory, antioxidant and anti-apoptotic properties. The aim of this study is to investigate the protective effects of IRN in lipopolysaccharide (LPS)-induced kidney injury. Material and methods: Twenty-four rats divided into three groups as control, LPS and LPS + IRN group. After 6 h of LPS administration, rats were sacrificed. Blood samples and half of the kidney tissues were collected for biochemical analysis and remaining tissues were taken for histopathological and immunohistochemical analysis. Results: In the LPS group, glomerular congestion and shrinkage, degeneration of distal tubules, mononuclear cell infiltration, cellular debris and intense proteinous accumulation in the tubules, increased expressions of Cas-3, nuclear factor kappa beta-p65 (NF-kB p65), levels of creatinin, TOS, OSI and decreased levels of TAS, AQP-1 were found significantly. IRN treatment reversed all these parameters. IRN's restorated AQP-1 levels by its anti-inflammatory, antioxidant and anti-apoptotic effects due to inhibiting NF-kB expression. Conclusion: This study suggests that IRN can be used in conditions affecting the kidneys such as AKI. Further studies needed for detailed molecular investigation of IRN at different doses and durations.