Since the use of insect cell lines for producing bio-pesticides and recombinant proteins is increasing, the establishment of new cell lines will help to enrich this industry. Therefore, several primary cultures were initiated from embryonic tissues of silkworm, Bombyx mori L. using both enzymatic and mechanical methods. The cultures were incubated in TC-100 medium supplemented with 10 and 20% concentrations of fetal bovine serum (FBS) at 27ºC. Among the methods used, homogenizing the embryonic tissue represented the best culture, which reached the confluence state sooner. Six different morphologies were distinguished in the embryonic primary cultures of silkworm including fibroblast-like cells with three sub-forms of A to C, spindle shaped cells, spherical cells and epithelial-like cells. Also, developing primary cultures from B. mori using enzymatic method is not recommended because of its low efficiency
