Through the combined analysis of six poem books of contemporary Spanish poetry, this thesis aims to define poetic writings and its rhythm. Rhythm is considered in relation with the notion of space. Starting with the traditional association of rhythm and meter, the first part studies how the metrical space of the writing of verses, with its structures and boundaries, involves the law and its transgression. On the other hand, the second part considers space as a “substance”: poetic writing is analyzed through its development in the language and sentences. Centered on the figure of the “line”, the second conception of rhythm also implies temporality, which is included in the words themselves (the verbs) and generated by the combination of the sentences. However, in the poem books, sometimes linearity is deconstructed by different phenomenon that deal with language (the dissolution of syntaxes), verse (the enjambment, the dissemination on various lines), and the page. The last chapter is dedicated to the visibility of writing on the page. As a concretization of the writing act, the page is also a revelation of the writer of the poem. Our third and last part is centered on the subject, its different faces and representations. Rhythm appears, at last, as a mosaic of discursive and semantic spaces that imply the speaker as much as the reader.