The effect for a chronic illness as cancer constitutes in a threat the life and has physical, psychological and social repercussions in elapsing of the existence. In the case of cancer of prostate, it is known that its treatment can intervene with the masculinity sexuality, causing loss of the sexual desire and erect dysfunction. Considering this reality, the objective of this work was to understand the way as men with cancer of prostate live deeply and attribute meanings to their sexuality. It was opted to the methodology of the qualitative research, in the perspective of the Martin Heidegger's Ontological-Hermeneutical Phenomenology. It was used verbal story of life as strategy of access to the stories of the collaborators. Ten men with cancer of prostate had been interviewed who had been submitted the treatments, with ages between 51 and 82 years, pertaining to economic classes D to B2. The results of the stories make possible the construction of five categories: 1) the temporality of infancy and the adolescence; 2) the temporality of the adult life: the affective marriage, family and sexual relationships; 3) the sickness: sexual affective relations after the experience of cancer; 4) the horizon of silence: what close and disclose the being; 5) life project. The interpretative analyzes exposed the pain and the suffering of these men when presenting erect dysfunction and aftermaths in their sexual performance, attribute of the ideal of masculinity happened of the patriarchal system. The pain experiences send the ways to it to exist authentic and fake. The fake way was observed in the refusal in accepting the fact of the existence, or either the acceptance of a body that ages, sickens and leaves to answer to the sexual desire. The effect for cancer of prostate elevates the contact with the proper end and some collaborators runs away to distresses that it appears when the last possibility is evidenced and more proper to exist: the death. These men search then, the available treatments for the erect dysfunction and project their future in the possibility to come back to have satisfactory erections, what express the dream of the lived sexual performance in youth. However, in this trajectory, some collaborators presents a way to exist authentic, evidenced for the understanding of the temporality of their existence. Their relates disclosed the conscience of that, for not being able to escape to the end, it remains to accept the modifications to them in the sexuality and in accordance with to live deeply their limits and possibilities. The way to exist authentic, that it constitutes the opening of the man to be able to be same itself, was disclosed in the affectivity and the dialogue of the collaborators with their partners. At this moment when the men lose the capacity to have erections and feel themselves fragile in their masculinity, if they allow expressing a basic aspect of the existence: the affectivity. The opening to speak about himself exactly and to hear his partner evidences the dimension of the care and th...