Ontological models have been formulated recently from different philosophical perspectives in order to explain the several modes of existence of musical works. The relevance of such investigations in the context of taking music as an object of aesthetic inquiry has sometimes been questioned, especially when considering the ways in which music is actually apprehended by listeners. According to some scholars, ontology has nothing to do with this topic. The present article aims to show in what sense it is appropriate not to ignore this field of investigation and its results. The meaning of ontological researches on music is discussed and some examples are presented and commented on. The interest of examining the criteria of identity of musical works is highlighted so as to understand the formulation of aesthetic judgements in varying cultural contexts.