Iran is home to a number of taxa of parasitic plants that are distributed in diverse ecological zones of the country. The present study examined the diversity and distribution patterns of these taxa. The geo-referenced dataset of Iranian parasitic species was formed using the distributional data available in “Flora of Iran” and “Flora Iranica” as well as several herbaria. To evaluate species richness and determine the main hotspots of parasitic flora in Iran, species distribution points were mapped on 0.25° × 0.25° grid cells using the Geographic Information System. In addition, the area-corrected species richness of parasitic angiosperms was calculated for each provincial unit. According to the results, the flora of Iran includes 104 species of 21 genera belonging to parasitic plant families that cover about 1.3 % of angiosperm species nationwide. Overall, the highest species richness occurs in parts of northwestern Iran and the Central Alborz. The richness of parasitic angiosperm species is very diverse among provinces of Iran. East Azarbaijan and South Khorasan provinces have the highest and lowest number of species, respectively.