The research entitled "The Law of Inheritance of Islam in Indonesia (Study of Legal Development of Inheritance in Compilation of Islamic Law and Practice in Religious Courts)" This research uses normative juridical approach, in collecting data more emphasized on primary source material, in the form of legislation, - the rule of law and the theory of jurisprudence associated with the problem in the Perusal.Based on these methods, the research produces basically: (1) Formulation of Islamic inheritance law in fiqh and Compilation of Islamic Law (a) Formulation of Islamic inheritance law in fiqih on al quran and al-hadist namely: Al Quran, QS. An-nisa (4): 7, QS. An-nisa (4): 11, QS. An-nisa (4): 12, QS. An-nisa (4): 33, QS. An-nisa (4): 176, QS. Al-anfal (8): 75, and Hadith Rasulullah SAW (b) The formulation of Islamic inheritance law in the Compilation of Islamic Law is set in Articles 171 to 193. (2) The development of Islamic inheritance law in the Compilation of Islamic Law in appeal to inheritance in fiqih which includes many elements of customary law and the interests that are needed by Indonesian society today, so many forms of inheritance law that has not been contained in the conventional fiqh (fiqh al-mawarits), but it has been contained and codified in the law of inheritance The Compilation of Islamic Law, among others: article 171 on common property, article 177 on the division of fathers asabah, article 209 which states that foster and adopted sons receive inheritance, and if they do not receive a will, it is entitled to a mandatory and compulsory law Islam also recognizes the property gono-gini fiqh although do not recognize; (3) The development of Islamic inheritance law in the practice of religious court ruling in Indonesia is not separated from the Compilation of Islamic Law is the Presidential Instruction. 1 In 1991 on 10 June 1991, so that marriage, inheritance and endowments for the followers of Islam have been established so that it can be used as religious courts as a "guide" in the sense that a guide for the judges of the Religious Court in deciding and settling the case, depends entirely from the Judges intended to put it in their respective decisions so that this compilation will materialize and have a firm meaning and foundation in the jurisprudence of the Religious Courts. In this way, the Religious Judiciary is not only obliged to apply the provisions outlined in the compilation, but it has a greater role to develop and at the same time complete it through the jurisprudence it makes.