Partial hepatectomy (PH) can be an inevitable surgical therapy in some conditions, such as hepatic malignancies, trauma or partial liver transplantation. Its capacity for regeneration distinguishes the liver from other essential organs. Regeneration is a complex process involving growth factors, cytokines, transcription factors, hormones, and oxidative stres products. In the event of ineffective or total absent liver regeneration, the lifethreatening picture of acute liver failure may supervene. In the present research, we studied the effect of leflunomide, a novel immunosuppressive and anti-inflammatory agent against autoimmune disease, on hepatic regeneration after PH in Wistar Albino rats.