An experiment was conducted to study the effects of adding vitamin C (L-ascorbic acid), vitamin E (µ- tocopherol acetate ) and their combination to diets on productive performance, egg quality and some blood plasma constituents of  Dokki-4 laying hens during  summer season in Egypt. The experimental period lasted from June to September, 2010. A total of 120, 30 weeks old Dokki-4 hens were randomly divided into four equal groups, each contained 3 equal replications.  First group was fed a basal diet (control group).The other groups were fed the basal diet supplemented with 250 mg vitamin C/ kg diet (group 2),150 mg vitamin E /kg diet
(group 3) and 250 mg vitamin C plus 150 mg of vitamin E (group 4).The results indicated that supplementation of  the basal diet with the combination of vitamin C and E (group 4) resulted in positive effects on final body weight, egg production, egg weight, egg mass, feed intake and yolk index as compared to those of the control group. However, feed conversion was numerically improved for the birds received the vitamin supplemented diets as compared to the control hens. Shell thickness was significantly (P≤0.05) improved with adding vitamin E alone or in combination with vitamin C as compared to their control counter parts. Blood Plasma protein was significantly increased in hens given vitamin C alone or in combination with vitamin E compared with their controls Plasma cholesterol concentration was significantly decreased, whereas plasma levels of calcium and phosphorus were significantly increased response to dietary single and combined addition of vitamins C and E as compared to those of the control group. Dietary supplementation with 250 mg ascorbic acid plus 150 mg vitamin E proved to be an effective practice for alleviating the adverse effects of heat stress on Dokki-4 laying hens during summer season in Egypt.