Magnaporthe grisea is proposed as a comb.nov. for Ceratosphaeria grisea Hébert, the perfect state of Pyricularia grisea (Cke.) Sacc. Pyricularia grisea is very close morphologically to P. oryzae Cav., well known as the causal agent of blast disease on rice. Magnaporthe was recently established in the Diaporthales to accommodate a single species, M. salvinii (Catt.) Krause & Webster, which was described as the cause of stem rot of rice with conidial state known as Nakataea sigmoidea Hara. Based on a review of the taxonomic characters of Ceratosphaeria grisea, the desirability is discussed of its inclusion in the genus Magnaporthe.