In this article, we use data from the 2016 National Survey on Drug Use and Health (NSDUH) to examine the association between religious involvement and marijuana use for medical and recreational purposes in U.S. adults (N = 41,517). We also consider whether the association between religious involvement and marijuana use varies according to personal health status. Our results show that adults who attend religious services more frequently and hold more salient religious beliefs tend to exhibit lower rates of medical and recreational marijuana use. We also find that these "protective effects" are less pronounced for adults in poor health. Although our findings confirm previous studies of recreational marijuana use, we are the first to examine the association between religious involvement and medical marijuana use. Our moderation analyses suggest that the morality and social control functions of religious involvement may be offset under the conditions of poor health.