In Indonesia society, a lot of 2 children are born outside marriage. Basically the child has no relation with his father, thus in this case inheritance law is not applicable between them according to the Civil Code, the Islamic Law compilation ( kompilasi Hukum Islam) and the Customary Law. His right under the Civil Code will arise after the acknowledgement of his father or mother, while with the father and mother's family after the official statement. Based on the Islamic Law compilation. an illegitimate child is entitled to inheritance right from his mother ang hos mother's family and vice versa. Meanwhile, since no relation with his biological father exists, no in heritance right arise. According to the concept of customary law, an illegitimate children has a civil relationship only with his mother, the refore an illegitimate child will only acquire inheritance from his mother and his mother's family. The child will not be entitled to for the inheritance from his father because there is no civil relationship with his father.