Cosmopolitanism is one of the most controversial ideologies dealt with English literature. It focuses on multiple characteristic features a man, modern and contemporary, may carry. Features like being cosmopolite or world citizen, placeless, patriot, and free which could protect him or her from being alienated, estranged, fearful, and undignified. It has some similarities with other concepts like universalism, multiculturalism, and humanism. The need for being a cosmopolite comes from the harsh circumstances of modern and contemporary lives presented in literature due to wrong policies, vicious globalization, and social injustice. This research paper deals with the concept of cosmopolitanism socially and philosophically and applies it to two poems: Walter De la Mare’s “The Listeners” (1912) and Derek Mahon’s “Afterlives” (1975) modern and contemporary respectively. The paper also aims at tracing the concept in both poems and comparing them thoroughly in order to show how it is employed, expressed, and concluded. In addition, the paper answers the questions: What is the use of being a world citizen? What makes a man be so? How does a cosmopolite feel outside and inside his country?