A total number of 420 one day-old broiler chicks (Ross 308) were used in this study to evaluate the effect of dietary supplementation of sage plant (Salvia officinalis) leaves powder (SP) and ascorbic acid (Vit. C) On growth performance, and metabolic response of broiler chickens. Chicks were randomly divided into seven experimental groups each of 60 chicks. Chicks of the 1^st group fed on basal diets (starter and grower) and considered as a control group, chicks of the 2^nd, 3^rd and 4^th groups fed on basal diets supplemented with SP at a levels of 4, 8 and 12 g/kg diet, respectively. While, chicks of the 5^th, 6^th and 7^th group fed on basal diets supplemented with Vit. C at a level of 200, 300 and 400 mg/kg diet, respectively. The obtained results showed that chicks fed diet supplemented with SP at a level of 12 g/kg diet showed higher improvement in body weight, body weight gain , rate of growth, feed consumption and conversion, blood parameters, economical efficiency, carcass yield and decreased mortality rate followed by those fed diet supplemented with Vit. C at a level of 300 mg/kg diet then by those fed diet supplemented with SP at level of 8 g/kg diet. It could be concluded that SP supplementation at a level of 12 and 8 g/kg diet, respectively and vitamin C at a level of 300 mg/kg diet seemed to be adequate to achieve the favorite results and is being recommended from the economical point of view.