Fenthion, one of the systemic organophosphorous (OP) insecticides, is widely used in both agricultural and urban areas, and has dose-limited side effects such as hepatotoxicity. Evidence demonstrated that these side effects are closely related to oxidative stress. The present study aimed to investigate the effects of two antioxidants, namely curcumin and taurine, on the extent of liver damage induced by fenthion. Sixty male albino rats were equally divided into six groups and were given oral doses by gastric tube daily for 4 weeks as follow; the 1^st group (G₁) served as an untreated control group under the same laboratory conditions and was given distilled water, the 2^nd group (G₂) is curcumin group that received 100 mg/ kg b.wt of curcumin, the 3^rd group (G₃) taurine group that received 100 mg/ kg b.wt of taurine, the 4^th group (G₄) fenthion-treated group that received 0.001 mg/kg b.wt of fenthion, the 5^th group (G₅) received fenthion parallel with curcumin, and the 6^th group (G₆) received fenthion parallel with taurine. At the end of experiment, the animals of all groups were dissected and the blood serum was separated for measurements of aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT) activities. Small pieces of the liver were kept at –20 ºC till used for measurements of antioxidant/oxidative parameters as glutathione peroxidase (GPX), superoxide dismutase (SOD) and malondialdehyde (MDA), in addition to the histopathological, histochemical detections of glycogen, proteins and DNA, and ultrastructural examinations. The results showed that treatment with the used antioxidants reduced the extent of liver damage induced by fenthion; this was indicated by decreasing the serum AST, ALT and GGT activities, increasing the activities of hepatic GPX and SOD, and inhibiting hepatic lipid peroxidation (LPO). In addition, these antioxidants ameliorated the histopathological structure, increased the contents of glycogen, proteins and DNA, and improved the ultrastructure of the liver tissue.