The aim of the present study is to analyze the conception of time in six books of poems by José Hierro (1922-2002): Tierra sin nosotros (1947), Alegría (1947), Con las piedras, con el viento… (1950), Quinta del 42 (1952), Cuanto sé de mí (1957) and Libro de las alucinaciones (1964). It is suggested that the theme of time in Hierro´s poetry can be approached from three different points of view: existence, essence and consciousness. Furthermore, these three different perspectives are reflected in a chronological division of Hierro´s books of poems into three periods: existential poetry, intimist poetry and hallucinatory poetry. In order to develop and reinforce the thematic study, on the one hand, a comparative study is carried out that focuses on the relationship between poetry and philosophy, and, on the other, the thematic configuration on the surface level is considered. The methodological foundations that make it possible to achieve this objective are provided by Jean-Pierre Richard´s thematic criticism, Edmund Husserl´s phenomenology and Paul Ricoeur´s phenomenological hermeneutics. The dissertation concludes that Tierra sin nosotros and Alegría represent Hierro´s existential poetry, written during the post-war period and the reigning atmosphere of existentialism. Alegría, Con las piedras, con el viento… and Quinta del 42 constitute his intimist poetry. The second book, Alegría, is described as a “bridging book” between the first two periods. When the immediacy of the Civil War begins to fade, the literary scene shifts towards the more intimate theme of knowledge, and in Hierro´s poetry especially the phenomenon of time. In Quinta del 42, Cuanto sé de mí and Libro de las alucinaciones the reader encounters Hierro´s hallucinatory poetry. Quinta del 42 is another example of a “bridging book” between two periods. His hallucinatory poems transmit an extreme form of the search for inner truth which entails the deconstruction of time and space.