This study compares the different ways Indian Hindu and Korean Christian immigrants in the United States preserve their ethnicity through religion. Hinduism is an Indian native religion and thus Indian dialects, food, holidays and other cultural elements are embedded within the faith. As a result, Indian Hindu immigrants can and do maintain their cultural and subcultural traditions and identity by practicing their religious values and rituals at home without actively participating in a religious congregation. In contrast, both Korean Protestantism and Catholicism are ‘Western religions’ that have been popularized only recently. Since the Christian religious faith and rituals are not directly related to Koreans’ language, values, food and holidays, they cannot maintain their ethnicity simply by practicing the faith and rituals. Instead, they try to preserve their ethnicity by increasing their social networks and practicing Korean Confucian cultural traditions through their active participation in a Korean congregation. Despite their far more active participation in a congregation, Korean Christians have disadvantages compared to Indian Hindus in preserving their ethnicity through religion because of the incongruence between their religion and ethnic culture. The literature on religion and ethnicity in the United States is largely based on turn-of-the-century, Judeo-Christian, congregation-oriented immigrant groups. Consequently, it has emphasized participation in an ethnic congregation as the main source of ethnicity and neglected to pay attention to the nativity of a religion as significantly contributing to preserving ethnic culture and identity.