This thesis provides a sociological analysis of religious conversion in prison. In depth-interviews were conducted in order to obtain accounts of prisoners' experiences and subjective perceptions of conversion. Four main research objectives are addressed. Firstly, questions about prisoners' identity are considered. Secondly, the social processes involved in religious conversion are analysed, paying particular attention to the meaning of religious conversion for prisoners. Thirdly, an analysis of the role of religion in the everyday lives of converts is provided. Lastly, the process of personal change that accompanies conversion is discussed, to enhance the analysis of self-identity and personal change more generally. The way in which prisoners' self-identity was questioned prior to conversion is discussed. The importance of experiences other than imprisonment in this process is particularly highlighted. This thesis emphasises the role of both reflective and interactive processes in religious conversion. The ways in which self-reflection led to a contemplation of religious ideas is highlighted, as is how participation in religious activities drew individuals into religious life and belief These considerations are placed within the context of prison life. The role of religion in the everyday lives of prisoners is explored. In particular, the role of religion in enabling inmates to transcend the restrictions of the prison environment, and reconceptualise themselves and their lives, is highlighted. Although the thesis is about religious conversion within the particular context of the prison, changes in self-identity and behaviour are viewed more widely. The analysis highlights the ways in which self-identity is negotiated in everyday life, and emphasises the dual roles of self reflection and interaction in its construction and maintenance.