With the unprecedented rise in defunct ecclesiastical heritage across predominantly Christian Western countries since the twentieth century, adaptive reuse has emerged as both a critical conservation strategy and a source of ethical contention. This paper revisits key conservation challenges and explores contemporary approaches to the adaptive reuse of disused ecclesiastical sites. Drawing on a review of scholarly literature and online public discourse, it develops a typological categorisation of reuse practices and examines the controversies associated with selected categories. The findings highlight adaptive reuse as a vital mechanism for safeguarding architectural fabric, particularly where demolition or abandonment is the likely alternative. However, ethical tensions arise from both sacred-to-sacred and sacred-to-secular transformations, shaped by theological doctrines, public perception, and broader socio-political dynamics. The study underscores the importance of local, national, and international heritage policies in guiding sensitive and sustainable adaptive reuse practices.