The sugar – beet rib miner, Scrobipalpa ocellatella Boyd., is a pest that causes economic damage to sugar- beet plantations in different regions of the world. Experiments carried out at laboratory of Plant Protection Research Institute branch Sakha and laboratory of pests & plant Protection Department, National Research Centre, Egypt. Spores of fungal isolates harvested by rinsing with sterilized 0.5 % Tween 80 from 14 day old culture (PDA) media grown at 25±2ºc for B. bassiana and M. anisopliae. The 4th instar larvae and pupae of S. ocellatella were treated with the spores of B. bassiana and M. anisopliae using the concentrations of 1x106, 1x107, and 1x108 spores / ml. The egg deposited in groups, each of a single layer consisting of 2-14 eggs arranged in one or two rows. The highest mortality occurred in larvae by concentration of 1x108 was 100 % after 9th day from treatment when infection with B. bassiana but reached to 100 % mortality after 10 days with the same concentration from M. anisopliae. B. bassiana was the highest virulence against the pupae of S. ocellatella than M. anisopliae. LC50 when infected larvae with M. anisopliae and B. bassiana was 2.27x106 and 0.4 x106 respectively while when infected pupae was 1.92 x10 7 and 2.99 x10 6 respectively.