When giving references to Hadiths, scholars sometimes face the problem of multiple names for a certain author. In other words, an author may have been recorded with different first names, second names or pennames. In this respect, Sheikh Sadouqh claims that Mo’ az Ibn-Moslem and Mo’ az Ibn-Kathir are, indeed, one person. History books as well as books of Hadiths and citations have referred to Mo’ az Ibn-Moslem as Al-Hera, Al-Fera, Bayya Ul-Harvi wa Al-Nahwi and to Mo’ az Ibn-Kathir as Kasayie, Bayya Ul-Aksyeh, Sahib Ul-Aksyeh and Bayya Ul-Karabis. Reports on citations assume authenticity for Mo’ az Ibn-Moslem but not for Mo’ az Ibn-Kathir. Therefore, in case that these two persons are proved to be the same, Mo’ az Ibn-Kathir will emerge as an authentic figure too. As the evidence shows, due to the name resemblance, some recent scholars have attributed the longevity of Mo’ az Ibn-Moslem, as the real figure, to Mo’ az Ibn-Kathir, as the referential figure. According to the findings of this research, these two figures have been reported with the same social class, job and living place in many documents. Besides, they have been equally favored by Imam Sadeqh (pbuh). This brings one to the conclusion that Sheikh Sadouqh’ s claim about the sameness of these two persons is correct, and Mo’ az Ibn-Kathir is thus authenticated.