An experiment was conducted to investigate the effect of dietary supplementation of garlic on the heamato-biochemical response and performance of broiler chickens. Cobb 400 chicks (n=480) were randomly distributed into four groups, further subdivided into four replicates of thirty chicks in each group. The chicks were kept under uniform managemental conditions on deep litter system from day 0 up to 6th weeks of age. Significant (p<0.05) improvement were observed in the total leukocyte count, erythrocytic count, hemoglobin concentration, packed cell volume and differential leukocyte counts of the garlic treated birds. The serum biochemical parameters were also affected (p<0.05) at different levels of supplementation. Cholesterol decreased significantly (p<0.05) while there was significant (p<0.05) increase in the total protein, albumin, and globulin concentration of the garlic treated birds. The growth performance traits were best observed at higher level of supplementation. The study revealed that supplementation of garlic to the diet of broiler chickens has several beneficial effects. The best results were obtained at higher levels of inclusion i.e. 0.75% garlic supplementation in mixed diet improved the haematology and biochemical indices in broilers resulting in better growth, thus, may be recommended in broiler chicken production.