Diazinon [0,0-diethyl 0-(2-isopropyl-6-methylpyrimidin-4yl) Phosphorothioate ] is one of the widely used organophosphate pesticides to control pest insects in agriculture and veterinary medicine. Therefore, there is always the risk of human contact with this toxin. The present study was carried out to investigate the toxicopathologic effects of diazinon in male rabbits through dermal exposure. For this purpose, 12 adult male rabbits were divided into two equal groups of 6 rabbits. The treatment group (A) received diazinon through dermal exposure for 28 days. The control group (B) on the other hand was given ethyl alcohol, as solvent of the diazinon, using the same method. Blood samples were collected from marginal ear vein of the control and the treatment animals on day 0 and later on days 7th, 14th, 21th, 28th of treatment. The analysis obtained from the data revealed that diazinon affects the haematological and biochemical parameters in Group A. In fact, there was a significant decrease in red blood cell count and hemoglobin (Hb) in the treated rabbits (p<0.05). Diazinon increased alkaline phosphatase (ALP), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) level in the serum (p<0.01) and cholesterol level (p<0.05). Diazinon also significantly decreased triglyceride and total protein level of the serum in the treatment group (0.05). On day 28, the rabbits were euthantized and necropsy was done. The histopathological changes that were observed in the treatment group included necrosis of hepathocytes, fat degeneration and hyperemia in liver, interstitial pneumonia, hyperemia,...