The work was carried out at the Plant Protection Department, Faculty of Agriculture, AL-AzharUniv, Nasr City, Cairo, Egypt. In order to carry outcomparative study between organic and mineral fertilization for mulberry trees and its effect on cocoon parameters of silkworm. Silkworm is a monophagous insect that drives almost all required nutrients for its growth and development from mulberry leaves. Treated mulberry Morusalbavarrosa (local variety) leaves were offered to Thio1 of silkworm larvae four times per day. Theobtained results showed that the feeding of larvae on leavesmulberry of trees treated with green manure increased the fresh cocoon weight (0.796, 0.680g), cocoon shell weight (0.162, 0.126g), pupa weights (0.678, 0.568g), cocoon shell ratio (24.98, 23.10g), silk gland (0.361), cocooning percentages (89.6, 78%) and silk productivity (1.62, 1.29cg/days).