Cotoneaster Medik. is an important and taxonomically complex group due to numerous and variable forms. Therefore, it is an interesting object for taxonomical studies. Five new records, including Cotoneaster transcaucasicus Pojark., C. minutus G. Klotz, C. afghanicus G. Klotz, C. aitchisonii C. K. Schneid., C. ellipticus Hort ex Loudon are identified for the first time from Iran. Moreover, C. meyeri Pojark. and C. insignis Pojark. are reported for the second time for the Flora of Iran and for the first time based on exact location and sample collection. These taxa are compared with their closest relatives. A morphological key, taxonomic treatment, color photographs, and distribution map are provided for the mentioned species. All the introduced species belong to Irano-Turanian region or ecotones of Irano- Turanian and Eurosiberian regions.