This paper reviews evidence for a relationship between religion and he
alth. Hundreds of epidemiologic studies have reported statistically si
gnificant. salutary effects of religious indicators on morbidity and m
ortality. However, this does not necessarily imply that religion influ
ences health; three questions must first be answered: ''Is there an as
sociation?'', ''is it valid?'', and, ''Is it causal?'' Evidence presen
ted in this paper suggests that the answers to these respective questi
ons are ''yes,'' ''probably,'' and ''maybe.'' In answering these quest
ions, several issues are addressed. First, key reviews and studies are
discussed. Second, the problems of chance, bias, and confounding are
examined. Third, alternative explanations for observed associations be
tween religion and health are described. Fourth, these issues are care
fully explored in the context of Hill's well-known features of a causa
l relationship. Despite the inconclusiveness of empirical evidence and
the controversial and epistemologically complex nature of religion as
an epidemiologic construct, this area is worthy of additional investi
gation. Further research can help to clarify these provocative finding
s.