The concept of transmigration of soul (tanāsukh) is denied generally in Islam and particularly in Ithnā‘asharī Shī‘ism as well. The present paper examines the attitudes toward the concept in the two thinkers in Ithnā‘asharī Shī‘ism, a theologian Shaykh al-Mufīd (d. 413/1022) and a mystic philosopher Mullā Ṣadrā (d. 1050/1640).
 Shaykh never accepts the concept of tanāsukh, and he negates the eternity of soul, which may work as the basis of its transmigration, while his teacher Ibn accepts it. In order to deny tanāsukh, Mufīd refuses any kinds of interpretation to the texts of the Qur’ān and the Traditions, which may support the eternity of soul and then, possibly its transmigration. Mullā Ṣadrā does not accept tanāsukh in a usual sense, but accepts a certain type of tanāsukh, which takes place in the world of soul as a form of resurrection in his philosophical system of the tripartite worldview.
 The difference of attitude between the two thinkers may come firstly from their different historical positions concerning the establishment of the Ithnā‘asharī orthodoxy, and secondly from their different materials which they constructed their own system of thought.