Plurality in the field of religion embodied in the multiplicity of religions recognized legal in Indonesian, besides Islam there are Hinduism, Buddhism, Christianity, Catholicism, and others. One form of such relations are reflected in patterns of family law in Indonesia, especially in the field of marriage since the promulgation of law Number 1 year 1974 Marriage and legalization of compilation of Islamic law in Indonesian through Instruction The President of the Republic Indonesian number 1 year 1991, June, 10th, 1991. Legal basis of religion in the exercise of a marriage is a very important thing in the UUP, so that the determination of whether a marriage may depend on the provisions of the religion. This means also that religious laws stating marriage should not be, then it should not be according to state of law.The Authors use research method is a method of Normative Juridical approach to Study comparative law (Comparative Approach) is to compare different legal perspectives in the field of marriage, not just Islamic law but also Positive law in Indonesian. The theory being used i.e. the theory of Obedient law in Islamic law and Islamic Personality Principle.The results of this research show that the transition of religion in Indonesian is not only being a discussion and legal problems in religion but is also regulated by the State in the form of positive law with the enactment of Indonesia UUP and KHI until recently became the legal basis for those doing legal form of marriage, especially for couples who change religion. So the couple that did the deed in the form of law the marriage despite later going on a dispute over the marriage, then the legal basis which can be used for them is legislation in Indonesia that is Islamic law, KHI and UUP.