Treatise of Mofa??al is one of the Shiite’s hadith heritages known as dictation by Imam Sadiq (pbuh) to Mofa??al bin Omar Jof?. This book has been studied in this essay in order to evaluate its validity in terms of its attribution to Imam Sadiq (pbuh). Reputation, acceptance reflected in numerous prescriptions, descriptive books, and multiple translations are some evidences documented for correctness of its attribution. Then, textual criticism employed for evaluation of its authenticity, so we approach the truth by different methods of intra-textual and extra-textual criticism. Numerous similarities between this book with others lead to doubt about its attribution to Imam Sadiq (pbuh).