Plagiarism in poetry is negotiated and understood via a series of tacitly agreed-upon techniques, which allow space for artistic practices of allusion and intertextuality, but also opens up increasingly complex concerns when poets fail to abide by these unspoken conventions. The techniques poets adopt to acknowledge or conceal their sources are wide-ranging but frequently under-represented in debates and scholarship about plagiarism, which more frequently focus on the moral and ethical arguments for and against using another's work. In this paper, we will argue that disclosure and documentation-through epigraphs, notes and other means of acknowledgement-are central to the so-called ‘cento defence’, allowing the poet to present the work of others as their own, whereas alterations, especially minor substitutions, and the absence of disclosure, are central to current conceptions of plagiarism. In doing so, we seek to define and make explicit the tacit conventions in contemporary literary practice relating to theft from the perspective of the poet-practitioner.