Nowadays, the puplic health faces a major proplem of increased pesticides use with appearing of various side effects. One of the most commonly used is diazinon. It exerts its effects on variable tissues and cells including hepatocytes. This work aimed to study the tendency of diazinon to cause hepatic affection in rats and study the possible propolis protective role. We used 30 rats, divided into 4 groups; group Ia (-ve control); group Ib (+ve control, corn oil group); group II (propolis group; 400mg /kg/day orally); group III (diazinon 20 mg/kg/day orally); group IV (diazinon 20mg/kg/day + propolis 400mg /kg/day orally) for 8 weeks. We studied biochemical parameters: serum aminotransferases (ALT and AST), tissue oxidative stress markers (hepatic MDA, hepatic catalase and hepatic GPx activities). Liver will be examined by light microscope to evaluate histopathological changes and immunohistochemical reaction to caspase 3 to predict apoptosis. Results indicated: Significant increase in the serum levels of the ALT and AST as well as hepatic MDA of diazinon treated rats compared to control group, whereas both hepatic catalase and GPx activities were significantly decreased these results had significantly improved in both propolis and diazinon group. Light microscopic examination revealed disruption in hepatic histoarchitecture in diazinon group unlike that in group III which returned near normal; while immunohistochemical staining showed many positive reacted cells to active caspase 3 in diazinon group which became few in group III near to control. In conclusion, this study demonstrated that diazinon may have hepatotoxic effects which can be protected by co-administration of propolis in adult rats. Further studies about diazinon effect on liver and about propolis role in hepatoprotection are recommended