The recent investigation was carried out at the Department of Plant Protection, Faculty of Agriculture, Al-Azhar Univ., Nasr City, Cairo, Egypt. The comparative Study on two hybrids of silkworm Bombyx mori (HoxK1xR3xT3) from (Produced by sericulture and agriculture experiment station, Vra Tza, Bulgaria silkworm) B.mori, were obtained from the Sericulture Research Department of Plant Protection Research Institute, Agricultural Research Centre, Giza- Egypt, and (J444) native hybrid reared on mulberry leaves Morus albavar. kanava-2. silk production as well as quality of silk cocoon depends on the nutritional value of mulberry leaves and larval growth. Obtained results illustrated that feeding of silkworm larvae of imported hybrid previously highlighted by breeding programs for production of superior domestic hybrid for adoption in the breeding programs in Egypt presented higher and consistent growth rates than the native one for all the developmental stages, such as grown larvae weight, larval duration, fresh cocoon weight, cocoon shell weight and, cocoon shell ratio, pupa weights, pupation ratio, cocooning percentage and silk productivity. Moreover, technological parameters included filament length, weight and size (denier). Also, such feeding led to shorter larval duration and decreased larval mortality percentages.