Three species of Macrosiphum(Unisitobion) are recognized from the Korean Peninsula, among which M.(Unisitobion) sorbi matsumura, 1918 and M.(Unisitobion) perilae(Zhang, 1988), comb. nov. are new to the Korean Peninsula. Morphological characteristics are discussed with the microscopic photos. Two species, M.(Unisitobion) sorbi and M.(Unisitobion) perillae are redescribed. The subgeneric position of each species is discussed. The host plants, brief biology, and a key to all known species of the subgenus are also presented.