Religion is a cause of many of the world's violent conflicts. This chapter focuses on religious identity in Northern Ireland and examines the nature and extent of religious conviction as well as its role in perpetuating communal division. It outlines the role of religion in relation to the Northern Ireland conflict. The chapter also focuses on the nature and extent of religious differences. Building on this analysis, the chapter assesses the role of religion in perpetuating or ameliorating communal division. Using census data from 1951 onwards, the results demonstrate the high rate of religious belonging, as measured by religious affiliation. In 1951, 95 per cent of individuals claimed to belong either to the Catholic faith or to one of the three main Protestant denominations. The chapter examines the issue using the 2007 Life and Times Survey, which contained specific items designed to measure religious identity.