An attempt has been made in this paper to look into Allameh Tabatabaee’s theoretical and basic principles on the authority and trustworthiness of akhbar (traditions) – including narrations from the Prophet (p.b.u.h.), Ahl al-Beyt (the Prophet’s household), the Companions and the Successors – as well as his practical conduct in discussions on narrations in Tafsir al-Mizan. Almost all that Allameh has done with regard to the trustworthiness or lack of trustworthiness of single traditions, authenticity of narrations or narrators in the process of transmission have been surveyed and their various applications in Islamic jurisprudence and other areas have been identified. On the basis of his main and usual approach, Allameh does not mention the documents of narrations and only analyzes their content. Here, however, he mentions the complete documentation of narrations, at times, and, in some other cases, he gives the name of the last narrator, traces the narration to its main source and may declare some narrators weak; he doesn’t consider single traditions authoritative in non-jurisprudential questions, is cautious towards Cause-of-Revelation narrations due the frequency of forgery and distortion among them and considers People of the Book as the main agents who paved the way for Isra’iliyat to find their way into the field of hadith.