Magnaporthe oryzae, a filamentous ascomycete fungus, is well known as the causal agent of rice blast. With thetechnology of suppression subtractive hybridization (SSH), it was previously found that MGG_06001 (or named MoNEM1),a gene of M. oryzae homologous to the NEM1 (nuclear envelope morphology protein 1) gene of baker’s yeast(Saccharomyces cerevisiae), is differentially expressed between the mature appressium and the conidium and mycelium.This study aimed to characterize the function of MoNEM1 gene by knocking it out using the method of target genereplacement. The ΔMonem1 mutants exhibited reduced mycelial growth and conidiation. However, disruption of MoNEM1gene does not affect the pathogenicity of M. oryzae on barley and rice.