<![CDATA[The Office of Religious Affairs (Kantor Urusan Agama/KUA) plays a strategic role in fostering sakinah families in Indonesia. This article examines the functions of the KUA through an ontological approach, with a specific focus on KUA Kecamatan Medan Barat as the locus of study, by analyzing the nature of its existence, fundamental structure, and institutional relations within the systems of Islamic law and the state. The study employs a qualitative method combining a philosophical ontological analysis of regulations and policies with field observation and documentation at KUA Kecamatan Medan Barat. Data were collected through document analysis of statutory regulations, Ministry of Religious Affairs policies, relevant literature, and direct field data gathered from KUA Kecamatan Medan Barat. The findings indicate that ontologically, the KUA has three dimensions of existence: as a representation of the state in religious affairs, as an institution implementing Islamic law, and as a social institution responsible for community development. At KUA Kecamatan Medan Barat, these three dimensions manifest in its pre-marital guidance programs, marriage counseling services, and community empowerment activities within the socio-cultural context of Medan Barat. The function of fostering sakinah families is not merely an administrative task, but a manifestation of the state's responsibility to promote family welfare based on Islamic values. This article concludes that an ontological approach provides a deeper understanding of the essence and substantive meaning of the KUA's functions, which are not limited to marriage registration but encompass holistic and sustainable family development]]>
