If death is revealed to us, in our human experience, as a certainty, one of the decisive questions of explaining our human condition aims at questioning and justifying this certainty. One of the authors who tackles this question is the German thinker, Martin Heidegger. According to him, death is understood and described, through a phenomenological and hermeneutical explanation, as an inner existential possibility as an ontological condition of the human being. This understanding has received various criticisms from contemporary philosophers. One of these belongs to Bartrand Schumacher who sustains that the only ontological understanding of existence cannot provide a certainty of its own end. In this way, Schumacher opposes an ontic meaning to the Heideggerian ontological understanding of death. In response to Schumacher’s critics we propose to look more deeply at the concept of possibility as the key-concept in the Heidegger’s ontological understanding of death.