Background & Aim: A feeding trial was conducted to investigate the effect of periodically use of garlic on growth ‎performance, and antibody titer to Newcastle and infectious bursal diseases in broiler ‎chickens. Experimental: Ross broiler chicks randomly allocated into the 10 dietary treatments ‎for 6 weeks. A 3 × 4 factorial experiment was used as three periods of feeding (starter, grower and ‎finisher) and four levels of garlic powder (0, 0.5, 1 and 3 %). Results & Discussion: Feed intake was significantly higher in control group (ppppp Industrial and Practical Recommendations: According to the findings, garlic powder, because of having antibacterial properties and other composition, can have some positive effects on growth function and immune system of broiler chickens. So, using it in culture units and producer companies of animal food for producing of healthy and organic production can be recommended. Manuscript profile