Background & aim: Many researchers believe that religious doctrines have persistent effects on the mental and physical health and other aspects of human life. This study aimed to investigate the effect of pregnancy-related religious training on religious attitudes among pregnant women. Methods: This interventional study was conducted on 84 pregnant women with low and medium levels of religious attitudes in 2013. The study population was randomly divided into two groups of intervention (n=42) and control (n=42). The intervention group received religious education within the gestational weeks of 20-28 in six sessions. The control group received routine hospital trainings. The two groups filled out the religious attitude questionnaires before, immediately after, and two months following the intervention. The data were analyzed with SPSS, version 16, using t-test. Results: The results of the independence t-test revealed no significant difference between the two groups regarding the level of religious attitudes before the intervention (P=0.936). However, there was a significant difference between the two groups in this regard immediately after the intervention (P=0.001) and two months post-intervention (P=0.001). The level of religious attitudes increased from weak and moderate to a high rate following the intervention. Conclusion: Given the positive impact of religious education on religious beliefs and attitudes, it is recommended to use this potential in prenatal care planning