An experiment was conducted to assess the influence of dietary benzoic acid supplementation on productive performance, egg hatchability, some blood parameters, intestinal Enterobacteriacea count, jejunum intestinal morphology and nitrogen retention for Sinai chickens. Sinai chickens as Egyptian breed were fed diets supplemented with different concentrations of benzoic acid consisting of 0 mg/kg diet (T1) and considered as control, 500 mg/kg diet (T2), 1000 mg/kg diet (T3), 1500 mg/kg diet (T4) and 2000mg/kg diet (T5). Egg number, egg mass and egg production percentage for chicken groups supplemented with 1500 and 2000 mg benzoic acid /kg diet, respectively were significantly improved compared to the rest of the experimental groups. Also, supplementing the diets with benzoic acid significantly improved feed conversion ratio for T5 group followed by those of T4 and T3 groups compared with the others. All doses of benzoic acid supplementation significantly improved eggshell strength and eggshell Ca concentration compared to those for control. Supplementing the diet with 2000mg/kg significantly improved the villus height and its surface area compared with control. Alsoexperimental doses of 1500 and 2000mg benzoic acid/kg diet significantly reduced the total count of gram negative bacteria in the jejunum. Moreover, the birds fed diets supplemented with all levels of benzoic acid except that of 500 mg recorded the lowest (P<0.0001) value of N excretion (g/day). Supplementing the diet with concentration of 2000mg benzoic acid (T5) significantly improved hatchability of fertile eggs percentage and hatched chick weight. It is concluded that supplementing the chicken diet with doses of 1500 or 2000 mg/kg diet benzoic acid had beneficial influence on egg quality, egg production%, jejunum intestinal morphology, hatchability% and loading reduction of harmful bacteria in the intestine.