Natural silk is mainly produce by mulberry silkworm and considered as a queen of textile. Nowadays, natural silk is used for treated many human diseases and used in many useful cosmetics for skin and hair. The aim of silkworm breeding is not only to synthesis the new genotypes but also to adjudicate the best hybrids for commercial exploitation. This work aims to study effect of hybridization of some local entries including 5 univoltine and 6 bivoltine mulberry silkworm, Bombyx mori L. entries which were selected and inbred to isolate pure lines.