The authors use recent data from the 2006 National Family Health Survey of India to explore the relationship between religion and demographic behavior. They find that fertility and mortality vary not only between religious groups, but also across caste groups. These groups also differ with respect to socio-economic status. The central finding of this paper is that despite their socio-economic disadvantages, Muslims have higher fertility than their Hindu counterparts and also exhibit lower levels of infant mortality (particularly female infant mortality). This effect is robust to the inclusion of controls for non-religious factors such as socio-economic status and area of residence. This result has important policy implications because it suggests that India's problem of "missing women" may be concentrated in particular groups. The authors conclude that religion and caste play a key role in determining the demographic characteristics of India.