Marriage as a legal action is an act that contains rights and obligations for the individuals who do it. The purpose of this study is to find out and analyze the Law of the Marriage Agreement on Property after the Marriage and, secondly, to analyze the legal force of the Marriage Agreement before a Notary after the Marriage takes place. Based on the results of research on the contents of Article 29 paragraph (1) of the Marriage Law, it limits the making of a marriage agreement for the separation of assets, but over time the Constitutional Court Decision No. 69/PUU-XII/2015, which has expanded the meaning of the marriage agreement where the marriage agreement is no longer interpreted only as an agreement made before Marriage but can also be made during the marriage bond. One of the public officials authorized by the state to do authentic deeds is a Notary. In the case of a marriage agreement based on the Constitutional Court Decision No. 69/PUU-XII/2015, the notary has the function of ratifying the marriage agreement. The ratification is in the form of an agreement made in a notarial deed. If the marriage agreement is made in a Notarial Deed, it can function as crucial evidence and have perfect evidentiary power. With the Constitutional Court Decision 69/2015, the marriage agreement is no longer interpreted only as an agreement made before Marriage (prenuptial agreement). However, it can also be made after the marriage (postnuptial agreement). Even though Constitutional Court Decision 69/2015 was requested by Indonesian citizens who are married to foreigners (mixed marriages), Constitutional Court Decision 69/2015 also applies to married couples of fellow Indonesian citizens.