During a first faunistic survey on the eriophyoid mites of Meshginshahr rangelands in Ardabil province, Iran, two new Aceria species of eriophyid mites were found, and they are described and illustrated. They are: Aceria ayvatliorum Lotfollahi et Hemmatzadeh sp. nov. from Rhaponticum repens (L.) Hidalgo (Asteraceae), and Aceria beygdiliorum Lotfollahi et Hemmatzadeh sp. nov. from Astragalus compactus Lam. (Fabaceae). The first aforementioned new species is the third eriophyoid associated with R. repens. And the second new species is the fourth Aceria species found on Astragalus species. Both new species were vagrants, and no plant deformations were observed. Due to the presence of numerous endemic Astragalus species in Iran, an intensive and cohesive survey of eriophyoid mites of Astragalus is strongly suggested.