Two hundred Ross 308 male one-day-old broiler chicks were applied to investigate the effect of phytogenic feed additive (PFA), characterized by phenolic terpenes, hydroxphenylpropenes flavones, phenolic acids, and aldehydes, on growth performance, some serum biochemical parameters, the gene expression profile of anti-oxidant enzymes, and economic efficiency. They were randomly assigned to one of four experimental treatments with five replicates per treatment (50 birds/treatment; 10 birds/replicate). Birds were fed with diets supplemented with 0 (control), 0.05, 0.10 and 0.20% PFA following a 3 phase (i.e., starter, grower and finisher) feeding program for 42 days. PFA supplementation significantly improved (P<0.05) the different growth performance parameters including weight gain, feed intake and feed conversion ratio. Furthermore, dietary PFA significantly reduced (P<0.05) the serum total cholesterol, and LDLcholesterol levels as compared to the control diet. The highest gross margin, benefit-cost ratio, economic efficiency, and lowest cost/kg were recorded in the broiler group fed on 0.20% PFA. Also, PFA dietary inclusion at 0.20% significantly augmented (P<0.05) the gene expression of GST/GAPDH, SOD/GAPDH and Catalase/GAPDH genes, compared with the un-supplemented controls. Birds fed diets containing 0.20% PFA exhibited the highest growth, economic efficiency, and gene expression. It could be concluded that supplementation with PFA in broiler chicken diets has beneficial effect on growth performance and biochemical parameters, and also improved economic efficiency through maximizing both returns and gross margin as well as gene expression profile of anti-oxidant enzymes.