Exposure of rats to As caused a significant increase in liver TBARS compared to control, but the co-administration of Se was effective in reducing its level. The activities of glutathione peroxidase (GPx) and glutathione-S-transferase (GST) of As-treated group were found lower compared to the control and the Se-treated group. The co-administration of Se had an additive protective effect on liver enzyme activities compared to As-treated animals. On the other hand, a significant increase in plasmatic activities of AST, ALT and ALP was observed in As-treated group. The latter was also exhibited a decrease in body weight and an increase in liver weight compared to the control. The co-administration of Se has decreased the activities of AST, AST and ALP and improved the antioxidant status as well. Liver histological studies have confirmed the changes observed in biochemical parameters and proved the beneficial role of Se. To conclude, results suggest that As exposure enhanced an oxidative stress by disturbing the tissue antioxidant defense system, but the Se co-administration protected liver tissues against As intoxication probably owing to its antioxidant properties.