The effect of ascorbic acid as a food additive, was tested on mulberry silkworm Bombyx mori. The present data show that ascorbic acid at different concentrations (0.25, 0.5, 1 and 2 % ) increased significantly the weights of both larvae and pupae. Fifth instar larvae of B. mori fed on mulberry leaves treated with ascorbic acid produced heavier fresh cocoons. Statistical analysis of data showed that 2 % ascorbic acid produced the heaviest cocoons. It enhanced silk production 29.85 % of the control. In addition, ascorbic acid proved to exhibit a significant effect on the increasing of the fecundity of emerged females.Furthermore, physiological studies have been carried out to explain the above mentioned effects of the vitamin. The tested concentrations of ascorbic acid raised the coefficients of food utilization and growth of mulberry silkworm larvae. Moreover the present study shows that vitaminC as a food additive, affected significantly the CA volume and increased the juvenile hormone level. 0v P in .-% /+O 5 $ -3 J 0 C 3.5