At present, researches have not reached a consensus on the relationship between religion and institutional trust. Based on the data from Taiwan and Japan, this study evaluated the impacts of several religion-related variables on personal institutional trust in different models. The study had following findings: (1) Religious affiliation had significant positive effects on institutional trust; (2) Religious behavior rather than religious belief has a positive effect on institutional trust; (3) The effect of religious affiliation disappeared after religious piety is included in the model. Also the religious piety has an independent, positive effect on institutional trust; (4) Civic virtues related to religions reinforced institutional trust.