My dissertation examines the works of three poets, Aratus, Apollonius of Rhodes, and Nicander, as scientific poetry. Rather than focusing on either literary or scientific material within them, I show that such a distinction is artificial and both literary and scientific interests are reflected in all aspects of these works. I argue that we should view the poems as serious attempts to discuss scientific matters, and that their intent to do so also impacts their own understanding of their poetry. In the introduction, I establish the parameters of my project, explain my definition of science, and discuss the lines of argumentation ancient scholars used to address the question of a poetâ??s authority to speak about scientific subjects. In my first chapter, I address Aratusâ?? Phaenomena as a poem about signs. Aratus ties his astronomical and meteorological information together through the unifying theme of semiology, and he focuses on the human ability to recognize signs and use them for practical purposes. My second chapter addresses Apollonius of Rhodesâ?? position within contemporary geographical debates, in particular about the use of Homer as a source. Apollonius uses his poetry to argue not only that Homerâ??s geography is authoritative but also that epic poetry has a prominent place in the discipline. In my final chapter, I focus on how Nicander establishes his relationship with Aratus as a way of legitimizing his subject of study, toxicology, and as a place of departure to secure his own position in the poetic canon. Nicander evinces a particular interest in taxonomy, and experiments with several different ways of organizing his information, while also exploring human mortality and the dangers of interactions with nature. All of this is united in his interest in names, as a means of differentiating species of venomous snakes and as a means of counteracting mortality by ensuring oneâ??s legacy. Each of these poets has a different goal in their works, but none of these can be cleanly separated into the literary and the scientific.