Interfaith marriage has not been clearly regulated in Indonesia’s Marriage Law. Article 2 paragraph (1) of Law Number 1 Year 1974 concerning Marriage which only states that a marriage can be said to be valid if the marriage is held based on the law of each religion. However, that doesn’t mean that interfaith marriages cannot be conducted in Indonesia. These marriages can be carried out by submitting an application to the District Court so that the marriage can be recorded at the Population and Civil Registry Office, as stated in article 35 letter a Law Number 23 Year 2006 concerning Population Administration. This thesis will specifically discuss how to regulate the registration of interfaith marriages in Law Number 1 Year 1974 concerning Marriage and Law Number 23 Year 2006 On Population Administration. In addition, this thesis will also discuss the practice of recording the marriage of married interfaith couples who have married religiously, based on the Decree of the Surakarta District Court Number 454/Pdt.P/2018/PN.Skt. The method used in this study is empirical normative, with a law approach and case studies that occurred in the Surakarta District Court. The results of this study indicate that there is no special regulation regarding mixed, especially interfaith marriages. However, married interfaith couples can register their marriage by submitting an application to local District Court.