Countries around the world have experienced substantial gains in life expectancy at birth and old age in the last decades but whether these gains represent quality and healthy years is still in question. External factors such as better diagnosis and treatment undoubtedly contribute to healthy aging but there is growing evidence that factors internal to the individual, including religiosity and spirituality, are equally influential. Nevertheless, research on religiosity, spirituality and health tends to focus either on morbidity or mortality; rarely on both combined, and this research has seldom examined findings across diverse populations. Health expectancy is a comprehensive measure combining morbidity and mortality that can establish whether extra years are healthy ones. Thus our Big Question is ‘Regardless of nationality, culture, or religious denomination, do people with deeper religious and spiritual conviction live longer, healthier lives? ” We address this question using rigorous contemporary methods and statistical software. Adopting national surveys from over eighty countries we examine if the question is generalizable across populations, cultures, and ways of expressing religious conviction. Using a range of health measures, including mental and physical, we see whether religiosity and spirituality impacts on specific health outcomes. Considering longitudinal panel data, we gauge where religiosity and spirituality impart their effect – through reducing the incidence of ill-health, enhancing recovery, or both. By adding a module to the U.S. Health and Retirement Survey we will be able to examine the extent to which the influences of religiosity and spirituality are set in motion at an early age. Publishing in leading journals and disseminating results at scientific meetings will increase awareness of the universality of and variation in health impacts of spirituality and religiosity around the world.