The effects of (-) epigallocatechin gallate (EGCg) on the morphology of hyphae and conidia of Trichophyton mentagrophytes were examined using scanning and transmission electron microscopy. EGCg inhibited the germination of conidia and subsequent hyphal growth. After being treated with EGCg for 3 days, conidia showed morphological changes such as deformation, swelling, wrinkles, exfoliation of the surface layer and accumulation of granular, amorphous materials on the conidia and short hyphae surfaces. These morphological changes became apparent day by day. After 5 days, most of the ungerminating conidia were broken down. The hyphal cell walls were also exfoliated and the cytoplasm in most of the cells disappeared completely. Inner organellas were variable in size and shape. Many high electron dense particles, greatly enlarged vacuoles appeared in the cytoplasm. The degradation of cells occurred. These observations indicates that EGCg causes lysis of the conidia and hyphae. These findings suggest that EGCg may be used as an antidermatophytic agent against T. mentagrophytes infection.