The impact of religiosity in suicidal behavior was evaluated in Brazil through a case-control study in which 110 subjects who had attempted suicide through the use of toxic substances were compared with 114 control subjects with no history of suicide attempts. Religiosity was measured in three aspects: organizational religious activities (ORAs), nonorganizational religious activities (NORAs), and intrinsic religiosity (IR). Multivariate logistic regression was used to evaluate the impact of religiosity on suicide attempts, controlling for sociodemographic variables, impulsivity, and mental illness. Religiosity, in its three dimensions, was shown to be an important protective factor against suicide attempts, even after controlling for relevant risk factors associated with suicidal behavior: ORA: odds ratio (OR), 0.63 (95% confidence interval [CI], 0.45-0.89); NORA: OR, 0.56 (95% CI, 0.42-0.75); and IR: OR, 0.59 (95% CI, 0.49-0.70). These data have important implications for understanding religiosity factors that might protect against suicide.