The science of ḥadīth holds a fundamental role in preserving the authenticity of the teachings of Prophet Muhammad ﷺ, and its historical development reflects an ongoing epistemological evolution within Islamic scholarship. Nevertheless, studies addressing the epistemological shifts within the discipline of ḥadīth science remain limited and insufficiently explored. This research aims to examine the contribution of al-Ḥākim al-Naisābūrī (d. 405 AH/1014 CE) to the formation of the epistemology of ḥadīth science. Employing a qualitative methodology with a content analysis approach, the study analyzes Ma’rifat Ulūm al-Ḥadīth as the primary source. Secondary data are drawn from academic literature discussing the development of ḥadīth methodology, including Nūr al-Dīn ‘Itr’s (d. 1442 AH/2020 CE) Manhaj al-Naqd fī Ulūm al-Ḥadīth, which proposes a classificatory framework of six branches of ḥadīth studies. The findings demonstrate that al-Ḥākim systematized fifty-two branches of ḥadīth sciences, expanding the methodological foundations laid by al-Rāmahurmuzī in al-Muḥaddith al-Fāṣil, while simultaneously providing a basis for modern reinterpretation by Nūr al-Dīn ‘Itr. The identified epistemological shift reveals a transition from a descriptive and taqlīd-oriented approach toward a systematic-analytical framework, and subsequently toward a reflective and systemic methodological orientation. al-Ḥākim’s contribution thus occupies a pivotal position in the evolution of the epistemology of ḥadīth science and offers a conceptual foundation for the development of ḥadīth methodology in the contemporary era.