The first step in the mushroom growing industry is the production of mycelium. Considering the effect of the type of culture medium on mycelial growth, the importance of choosing a suitable culture medium for propagation of pure cultures to produce span is not less than the choice of strain for crop production. Therefore, in this study, four different experiments were designed to evaluate the effect of pH, sugar beet molasses, B vitamins and growth regulators to induce maximal growth of Lentinula edodes mycelium on cereal extracts. The results showed a significant difference between treatments and their interactions. Overall, the studied fungus obtained the highest mycelial growth rate (10.4 mm / day) in sorghum extract with pH = 4.5. Nevertheless, the malt culture medium of agar extract with pH = 6 induced the lowest growth rate (7.6 mm / day). In addition, enrichment of the culture medium with molasses reduced the rate of vegetative growth. In this study, the lowest growth rate occurred in corn extract enriched with 3 g / l molasses (5.8 mm / day). On the other hand, sorghum extract enriched with 0.25 mg / l thiamine (B1 (12.9 mm / day) and wheat extract enriched with 1 mg / l nicotinic acid (B3 (8.3 mm / day)) In addition, they induced the highest and lowest growth rates. 9 mm per day) was the lowest growth rate.