The legal consequences of the resident in particular the mixed marriage which the parties get impediment to perform legal acts primarily to have the right to land due to the occurrence of rounding of the property along with foreign nationals where the regulations Legislation on land in Indonesia adhering to the principles of nationalism. The parties in the mixed marriage must make an agreement to marry a treasure at the time or before the marriage is held as it is mentioned in article 29 of the Marriage Act (UUP). The issue arises for mixed marriage parties that do not yet have a mating agreement in which legal protection for Warga-negara Indonesia maintains Kewarga-negaraannya is very noted. In writing this author uses a research method of normative juridical approaches which are sourced from secondary legal substances by understanding the law as a regulatory device or a positive norm in the prevailing legislation. However, after the decision of the MK No. 69 The law of marriage had a change especially concerning the marriage agreement in which the marriage agreement could be made during the wedding, which also applies to third parties during the agreement to be registered/ According to the prevailing laws and regulations.