The taxonomic revision of the genus Periophthalmus from Korea was made based on the fish specimens collected in the southern and western coasts of Korea from September 1983 to October 1994. The genus Periophthalmus in Korea was classified into two species : P. modestus and P. magnuspinnatus n. sp. P. magnuspinnatus differs from all other species of the genus by ventral fin united about two - third the fin and first dorsal fin relatively large, convex, distinct black submarginal band.