This longitudinal study assesses the associations between developmental trajectories of religious service attendance from mean age 14 to mean age 43 and nicotine dependence and alcohol dependence/abuse at mean age 43 (N = 548). Six trajectories of religious service attendance were identified. As compared with belonging to weekly stable trajectory group, a higher probability of belonging to the weekly/none decreasing, occasional stable, and non-attendance trajectory group was significantly associated with a higher likelihood of nicotine dependence. In addition, as compared with belonging to weekly stable trajectory group, a higher probability of belonging to the weekly/none decreasing, weekly/occasional decreasing, occasional stable, and non-attendance trajectory group was significantly associated with a higher likelihood of alcohol dependence/abuse. These findings are consistent with the hypothesis that religious service attendance protects against nicotine dependence and alcohol dependence/abuse in early midlife.