Four new Dactylogyrus species (Dactylogyrus pallicirrus sp. n. from Cyprinion macrostomum and Cyprinion watsoni, D. rohdeianus sp. n. and D. capoetae sp. n. from Capotta damascina, and D. schizocypris sp. n. from Schizocypris hrucei) are described from endemic Iranian freshwater fishes. Comments on the monogenean fauna of Iranian freshwater fishes are presented.