The mission of the Catholic Church is evangelisation, the purpose of which is conversion. At a diocesan level, the mission is carried out through the agencies of family, parish and school. Every Catholic school is mandated to carry out its part in the Church's mission through its curriculum, which incorporates both religious education and planned catechetical experiences. This study was devised to find out about students' perceptions of their faith, how their faith developed, and how the imagination assisted their faith development and religious conversion. Fifteen Catholic secondary school students from four schools in the Archdiocese of Perth, Western Australia were interviewed in their final year of their studies and some were interviewed in the following year. Data analysis was shaped by interpretative phenomenological analysis (IPA), a model of how the imagination assist religious conversion was proposed and recommendations were made about how to assist the evangelisation of youth in Catholic secondary schools.