The pathogenicity efficiency among two of the entomopathogenic fungi (EPF), Beauveria bassiana and Metarhizium anisopliae against the last larval instar of the greater wax moth (GWM), Galleria mellonella L., under laboratory conditions was compared. The histopathological changes in cuticle and midgut at 48hrs post fungal infection was investigated. The results revealed that, the concentration–mortality relationship showed that larval mortality increase in a linear relationship with conidia concentration and B. bassiana causing higher mortality percentage with LC₅₀ 3.1x10²conidia/ml while LC₅₀ of M. anisopliae reached 4.6x10³conidia/ml. The histological analysis of B. bassiana infection at 48 hrs. post-infection showed extensive histopathological changes in cuticle and midgut that induced nodule formation beneath the cuticle layer and destroying midgut epithelium by separation of columnar layer towards gut lumen with increasing the number of regenerative cells beneath it.