Research and theory increasingly suggest that attendance at religious services is protective against premature mortality. However, prior studies are limited and do not extensively explore potential explanations for the relationship, especially in terms of religious beliefs and behaviors associated with service attendance. This study estimates the impact of service attendance on mortality in a national probability sample and provides the most extensive empirical examination of potential explanations. Individuals who report attending religious services once a month or more (just over 50 percent of the population) have a 30-35 percent reduced risk of death over a 7.5 year follow-up period after adjusting for potential confounding factors. Consistent with prior research, 20-30 percent of this effect may be explained by better health behaviors (especially physical activity) among regular service attendees. Surprisingly, other religious beliefs and behaviors do not explain, and often tend to suppress, the association between service attendance and mortality.