The demand for silk has been increasing day by day but the average silk production is not enough to meet its demand. In this study, we investigated the effect of amino acid supplemented mulberry feed on the biological and commercial traits of Bombyx mori L. (Lepidoptera; Bombycidae). The silkworm larvae at 5th instar stage were taken and fed with fresh and healthy mulberry leaves coated with Alanine, Glycine and Serine in fourteen different combinations. Results of the current study revealed that the average weight of silkworm larvae and the % ratio of silk gland to body weight on day 7 was significantly (P˂0.05) higher in the group fed with amino acid fortified leaves as compared to the control. The commercial traits of larvae fed with amino acid fortified leaves also improved significantly. The larvae fed with Alanine (1 %) treated mulberry leaves showed the maximum cocoon weight, cocoon length, cocoon width, cocoon shell ratio and fibroin content as compared to the control group. It is evident from the results that the amino acid (particularly alanine) coated mulberry leaves have a positive effect on the commercial and biological traits of Bombyx mori (L.).