This article analyzes different ontological categories and how they relate to the conservation of contemporary art. Faced with the necessity of apprehending the work of art from an ontological point of view, a theoretical approach is made on the concepts that most affect the conservation of contemporary art: quiddity, truth-authenticity, identity, quality, consistency, and interpretation. These are analyzed from an empirical perspective, based on the experience of conservation and restoration. Since conserving and restoring require making decisions that will affect the material and conceptual plane of the works, several possible paradigms that must be introduced into the deontological code of the profession are analyzed. In addition, the study of a new paradigm is provided, that of the death of the work of art. This paradigm can serve as a frame of reference, given the impossibility of bringing the ‘Truth’ of the artwork into the world of the sensitive. This may occur due to different conditioning factors and limitations of a material, technical, or intentional type, which affect issues that were once established as essential to the entity. On the other hand, different types of time that are related to the conservation of contemporary art are studied: biological time, the eternal present of the work, time as a constructor agent, and destructive time as a facilitator of the appearance of ruin or ruin-relic in the work of art.