The increasing influence of APG classification system necessitates an update on taxa recorded in most regional floras including Iran. Many changes in circumscriptions of families and orders have occurred in APG in comparison with other classification systems. However, here we only attempt to emphasize on changes in the Iranian flora, especially in comparison with “Flora Iranica” and “Flora of Iran”. Of the overall 132 family names which have been mentioned here, 22 families are not found in Flora Iranica. Based on the APG IV system, 21 families which had been mentioned in Flora Iranica for Iran should be merged with other families. Accordingly, the angiosperms of Iran comprise 8012 species, approximately 1234 genera and 132 families placed in 39 orders. Gymnosperms (17 spp.), ferns (60 spp.) and mosses (534 spp.) included, the number of plant species of Iran exceeds approximately 8628 species. The largest angiosperms families of Iran are Fabaceae (1401 spp.) and Asteraceae (1234 spp.) in terms of number of species, and Asteraceae, Poaceae, Apiaceae and Fabaceae in terms of number of genera. The largest angiosperm order of Iran in terms of family number is Caryophyllales. The largest genera of Iran are Astragalus with about 830 species and Cousinia with about 280 species. In the two latest versions of APG a linear sequence of families is provided to be used by herbarium curators.