Is there a link between feelings of existential insecurity and the strength of religious values? Previous work suggests such a relationship, but proxy measures of insecurity have been limited to noisy aggregate-level indicators, such as each society”™s level of per capita GDP. This chapter addresses these issues. We summarize the theory of existential security and review what we know and also the data sources and methods we use. We draw upon new evidence concerning from the 2005″”2007 World Values Survey conducted in 55 nations as well as from the 2007 Gallup World Poll conducted in 132 nations. The results reveal the impact of experiential security on religiosity, utilizing the Gallup Lived Poverty index. Building upon this foundation, we pay particular attention to perceptual or subjective measures of security and risk from the 5th wave WVS. We conclude that the dynamics of secularization are much more complex than the simple decline of religion proposed by some early theories or a universal revival of religion worldwide, as suggested by many contemporary commentators. We demonstrate that rising existential security brings declining emphasis on religion in many post-industrial societies worldwide. In short, there is a growing religiosity gap worldwide.