The objective of this paper is to show in Pope Francis' Laudato Si: on Care of our Common Home (2015), his ardent concern with ecology in its literature and his use of literary devices to enhance an effective response to the call for nature’s protection. The paper attempts to see to what extent Pope's religious encyclical can be considered a key text for literary ecocriticism. The methodology that will be used is obviously that of ecocriticism or green study. The paper also makes an investigation into the social teachings of Catholic Church that illustrate environmental concerns and on which Pope Francis grounds his arguments.