It has suited both sides of Ireland's religious and political divide to portray the Great Famine that affected Ireland in the late 1840s as primarily affecting the Catholic population. However, while the geographies of the Famine have been explored in detail in recent years its religious dimensions have been largely ignored, albeit with a few exceptions. As a consequence, the assumption that the Great Famine was a Catholic famine has not been sufficiently challenged. Drawing on a relatively untapped source, the 1834 Commission on 'the state of religion and other instruction in Ireland,' as well as census data, this paper explores the relationship between religion, poverty and population loss over the Famine period. It shows that Catholics were disproportionately affected by the Famine because the Famine was most severe in areas whose population was overwhelmingly Catholic. In more mixed areas, however, the Protestant population seems to have been at least as affected as Catholics if not more so. This conundrum explains why the Famine actually had a surprisingly small impact on Ireland's religious demography. (C) 2015 Elsevier Ltd. All rights reserved.