Diazinon is a widely used pesticide in agriculture. So, the current work aimed to investigate the effects of diazinon exposure on some physiological and biochemical parameters, as well as, histopathological changes and histochemical acetyl-cholinesterase activity (AChE). The red Baladi rabbits were dipped into water (Control Group), diazinon at low concentrations of 0.6 mg diazinon low concentration (DLC) or high concentration of 3mg diazinon high concentration (DHC) dissolved in 1l of water for 10s. Treatment was repeated after 10 days and animals were sacrificed between 0 and 21 days after the second treatment. Blood analysis revealed that Red blood cells (RBC's), hemoglobin (Hb) and plasma total protein (TP) were significantly decreased in both diazinon concentrations (P<0.01), (P<0.05), (P<0.01) respectively. Cholesterol and microsomal protein were increased (P<0.01), while, liver/ body weight and cytochrome P-450 were decreased in both concentrations (P<0.01). Also there was a highly significant effect of concentration X day interaction on all parameters (P<0.01). Histopathological changes of liver, kidney and brain were observed after DHC dipping. Glycogen content was decreased in liver and increased in kidney Bowman's capsule. Furthermore, AChE activity was inhibited in brain tissue, decreased in liver cells, but gradually increased in kidney glomerular cells. Therefore, kidney and brain were highly affected by diazinon exposure compared with the liver. Exposure of animals to diazinon caused extensive changes in physiological, biochemical, and histopathological parameters as well as histochemical AChE. So, contact exposure of diazinon leads to negative response on animal health.