Astragalus zarreianus. is described and illustrated from Iran. It belongs to section Astragalus. This new species confined to western part of Iran (Prov. Illam) from only one location. A key to the species of the section known from Iran is prepared. Differences between the section and the closely related sections are discussed. On the basis of some important trends, an informal grouping is undertaken for yellow flower Astragali. Moreover, A. pseudo‐orthocarpus is considered as a valid species in this treatment and differences with its closest relatives are described.