Contrary to its seemingly marginal appearance, respiration is a recurring theme throughout Merleau-Ponty’s work, consistently questioned and revisited as his embodied phenomenology evolves. In Phenomenology of Perception, reflections on breathing are closely tied to sleep, shedding light on le sentir, the perceptual body, and space. Later, respiration takes on a rhetorical dimension in questioning the distinction between human and animal institutions. Further elaboration emerges in “Eye and Mind,” where the theme of reversibility deepens its significance. This chapter examines Merleau-Ponty’s remarks on respiration in chronological order, tracing their development across his works. By synthetically considering these reflections, I demonstrate that Merleau-Ponty’s evolving ontology increasingly calls for a deeper understanding of respiration. Through fully opening toward a respiratory ontology, hermeneutical connections between time, space, and breathing will be established. The goal is to reveal how different levels of understanding breathing correspond to distinct perspectives on the origin of time and space. These levels ultimately culminate in the idea of respiration as the making of Being from within. I conclude the chapter by leaving the question open: What does it mean to interrogate a coorigin of time and space within respiratory ontology?