Proscription of synthetic growth promoters (SGP) in poultry production worldwide has encouraged scientists to seek out natural alternatives, such as herbal additives. This research aimed to investigate the possible impact of adding garlic, thyme, sage and their combination on performances of broiler chickens. A total of 180 unsexed, one-day-old Cobb 500 chicks were randomly dispensed into five treatments (3 replicates × 12 chicks per replicate). Dietary treatments were as follows; T1: control group; T2: garlic powder (Allium sativum, 5g /kg); T3: thyme powder (Thymus vulgaris L., 5g /kg); T4: sage powder (Salvia officinalis,5g /kg); T5: garlic + thyme + sage powder (5g /kg for each). Growth performance was evaluated throughout the 35-day trial. Results obtained reveal that tested supplements thyme and sage, significantly increased final body weight (FBW) and improved feed conversion ratio (FCR) compared to other treatments. While the sage or garlic groups significantly (P<0.05) had the highest carcass yield %, without holding significant differences (P > 0.05) for other carcass variables. All studied supplements had a significant appreciable lowering impact in decreasing blood serum, total cholesterol and lipids compared to the control. In addition, enhanced immunological indices (H/L ratio and antibody titer against Newcastle disease) and beneficial bacteria count in the small intestine of birds provided by supplemented phytogenics. In respect of the results, it can be concluded that adding 0.5% of the proposed additives to broiler diets could be utilized as an alternative to SGP due to the affirmative productive performance and immune-system of broilers.