Indonesia regulates the marriage problems of its citizens through Marriage Law No.1 of 1974. In the Marriage Law Article 2 paragraph (1) it is stated that marriage is valid if it is carried out according to the law of each religion and belief. The heterogeneity of religions adopted by Indonesian society in their interactions will have an impact on marriage. Quite a lot of cases of interfaith marriages that occur in society have not been well received and are still considered problematic. On the other hand, the Indonesian state already has a law on marriage, but this law does not explicitly mention interfaith marriage. This gives rise to multiple interpretations and a lack of legal certainty regarding interfaith marriage. Although it must be admitted that the issue of interfaith marriage has experienced a legal vacuum, on the other hand, carrying out marriage will not be unstoppable. The purpose of writing this article is to examine the polemics of interfaith marriage, its impact, and the legal review of Marriage Regulation and Kompilasi Hukum Islam. The results of the study, marriage between religions, although, difficult but widely carried out in Indonesia, shows that the level of diversity of the Indonesian people is still not strong enough so that practices that are prohibited by religion and regulated in the Law are still carried out. Keywords: marriage, different religions, Indonesia