Sixteen healthy native dogs aged about 2 years with average body weight of 22.5±1.5 kg of both sexes were selected for this study. Dogs were divided randomly into four groups (4 dogs/group). Clinical signs were recorded and blood samples were collected for laboratory examination before injection of venom. The control group was injected with 1ml of saline solution and the groups 2-4 respectively received 0.1,0.5 and 1mg/kg of the venom powder of VIPERA LEBETINA dissolved in 1ml saline solution, injected into the hind limb (biceps femoris) of each dog. Clinical signs were recorded and blood samples were collected at different time (10, 20, 30 and 60 minutes and 2, 4, 8 and 24 hours) after injection of venom examined for sedimentation rate, WBC count, number of neutrophils, RBC and platelet count, HCT, Hb concentration, MCV, MCH, MCHC, bleeding and clotting time, PT and PTT. The results were analyzed statistically.Results indicated that the main clinical signs were pain, pawing, weakness, whimpering, leash chewing, subcutaneous hemorrhage, hypotension and death in dogs in high doses. Heart and respiratory rate and body temperature in dogs of groups 2, 3 and 4 increased after injection of snake venom (P<0.05) which could be related to pain, stress and tissue damage at the site of venom injection. This resulted in an increase in body temperature due to release of pyrogenic substances especially in dogs of group 4. Number of white blood cells (WBC) decreased significantly (P<0.05) which could be related to stress and accumulation of white blood cells in the foci of exogenic factor and consumption of WBC and tissues damage. Comparison of means of platelets, indicated a significant difference in dogs of the group 3 (P<0.05). Primary decrease in the platelets of dogs is due to consumption of platelets in blood circulation at the site of venom injection and hemorrhage then increased due to body replacement. A significant increase (P<0.05) in coagulation, prothrombin and partial thromoplastin time in dogs of groups 3 and 4 was observed. This increase could be related to anticoagulant factor of the venom of this snake, which showed its effects in high doses. It is concluded that in addition to clinical signs and hematological changes, coagulopathy and hemolysis in high doses of VIPERA LEBETINA venom were the main effects on hematological parameters in this respect.