The genus Calendula belongs to tribe Calenduleae, (Asteraceae family). Itmorphologically studied for the ongoing project of the flora of Iran. Based on the herbarium studies and field observation, this genus has been revised. The study was based on fresh material from field as well as herbarium specimens. All specimens existed in the herbarium of Research Institute of Forests and Rangelands (TARI), herbarium of Iranian Research Institute of Plant Protection (IRAN), herbarium of Ferdowsi University of Mashhad (FUMH), Herbarium of Research center of Agricultural and Natural Resources of Fars, were revised. Description of genus and species with key of determination of species is designed. In this search the number of Calendula taxa increasing 9 and Calendula karakalensis Vass. Is presented as a new record for the flora of Iran also the checklist of accepted species have been prepared.