The Biostratigraphical significance and geographical distribution of nine genera of Late Devonian (Famennian) Rhynchonellid in the Central Iran and Alborz such as: Eoparaphorhynchus, Pampoecilorhynchus, Stanaulacorhynchus, Centrorhynchus, Leptocaryorhynchus, Gastrodetoechia, Megalopterorhynchus, Araratella and Paurogastroderhynchus were studied. Three species: Eoparaphorhynchus maclareni, Pampoecilorhynchus arianus and Stenaulacorhynchus cheshmehshirensis are index brachiopoda of Early Famennian. Also Leptocaryorhynchus jamensis is introduced as a index species of Middle Famennian in the Central Iran and Alborz. The species such as: Centrorhynchus turanica, Megalopterorhynchus chanakchiensis, Araratella dichotomians dichotomians, Araratella dichotomians assimulata, Paurogastroderhynchus nalivkini, Paurogastroderhynchus bikniensis are index fossils of Late Famennian.
Consequently, these brachiopods are very useful index fossils for precise biozonation Iranian Famennian sediments because they have wide geographical distribution and are short ranged.