The purpose of the present study is to explore the two concepts of time and space in postmodern lyric poetry of the two poets of the 1950s through the lens of the Heideggerian existential theory of time and space, which regards time as a horizon for understanding Being and distinguishes three different types of space: (1) world-space, (2) regions , and (3) Dasein's spatiality. To fulfill this objective, some selected poems of the two poets, including Allen Ginsberg and Ted Hughes, were analyzed temporally and spatially. The findings suggested that the two poets tend to treat time and space existentially and reject eternality. It was revealed that they are existential poets whose existence is manifested in their quest for identity within the immediate world or the global world as well as their concerns for their homeland and ideals. In their poems, time and space are intermingled with Being and reflect each individual’s relationship with the world. The result of the analysis of poems showed that their poetry is not just the language of imagination and perception, but also the language of existence. The world is regarded as an existential space-time continuum and being-in-the-world is the fundamental ontological situation for Dasein. Accordingly, the world, like poetry, is a disclosure of things in nearness or distance, which matters to human beings