This experiment carried out as a completely randomized design with six treatments and 3 replicates pens of 100 birds each (total of 1800 birds). Treatments were consisted of a common corn-soybean meal based starter and grower diets supplemented by 0, 0.125, 0.25, 0.5, 1 or 2% garlic meal. At 1-21 days of age, daily feed intake per chicks influences by dietary garlic meal level so that the birds fed diets with 0.125 and 0.25% garlic meal had a significantly higher daily feed intake (p < 0.05) than birds fed 0.5% dietary garlic meal. At 22-42 days of age and the whole experimental period (1-42 days of age), garlic meal level didn't affect daily feed intake. No significant difference recorded for daily weight gain of experimentally birds at 1-21 days of age, But at 22-42 days of age and the whole experimentally period (1-42 days of age) the birds fed the control diet (free of garlic meal) and the diet containing the highest garlic meal dosage (2%) had a significantly lower daily weight gain in compare to other birds (p < 0.05). At 1-21 days of age the birds fed diet supplemented with 0.5% garlic meal had a lower feed conversion ratio than the control birds (p < 0.05) but at 22-42 days of age and the whole experimentally period (1-42 days of age) birds fed the control diet and the diet whit 2% garlic meal supplement showed a higher feed conversion ratios in compare with birds fed diets containing 0.125, 0.5 or 1% garlic meal. No significant differences were detected in carcass percentage and interior organs between birds fed experimental diets. The weight gain reduction in birds fed 2% dietary garlic meal means that herbal additives have their limitations too and needs more investigation.