This manuscript entitled "Cassation Legal Efforts Against the Medan High Court Decision by the Defendant
(Case Study Number 7 / Perdata / 2019 / Medan High Court)" regarding the Analysis of the Case Analysis of
the Cassation Lawsuit filed by the defendant at the Medan High Court. 7 / Perdata / 2019 / Medan High Court
which is also related to elements of Batak customary law. The purpose of this research is to clearly determine
the inheritance rights of the defendant and also the defendant in Decision Number 7 / Perdata / 2019 / Medan
High Court looking at the considerations of Law Number 1 of 1974 concerning Marriage, Law Number 14 of
1970 concerning Basic Provisions of Judicial Power and their relation to Batak Customary Law. The legal
research method used in this paper is a normative juridical method with qualitative descriptive data analysis
method. The results showed that there was no legal protection for the defendant in the content of the Medan
High Court judge's decision that did not properly consider the evidence and facts that occurred in the field
accompanied by clear legal evidence and permanent legal force. The judge also did not properly consider other
factors, namely the Batak customary law that occurred in this case which was detrimental to the defendant in
the entire content of Decision Number 7 / Perdata / 2019 / Medan High Court.