Penelitian ini bertujuan untuk mengetahui dasar pertimbangan Hakim didalam menentukan kedudukan ahli waris anak luar kawin yang diakui dan menentukan besarnya warisan yang diterima oleh anak luar kawin yang diakui (studi kasus putusan nomer 554/PDT.G/2000/PN JKT PST dan putusan nomer 567/PDT.G/2001/PT.DKI). Penelitian ini merupakan penelitian hukum yang bersifat normatif. Yang dilengkapi dengan penelitian lapangan (empiris). Sehingga penelitian ini menggunakan dua jenis data, yaitu data primer dan data sekunder. Data primer diperoleh melalui wawancara, sedangkan data sekunder diperoleh melalui kajian pustaka dengan cara penelusuran bahan-bahan hukum yang bersifat sekunder, primer, dan tersier. Keseluruhan data yang diperoleh dianalisis secara kualitatif. Dari hasil penelitian, maka diperoleh kesimpulan sekaligus menjawab permasalahan yaitu bahwa dengan pengakuan terhadap anak luar kawin, timbulah hubungan hukum perdata antara si anak dengan bapak atau ibunya. Sehingga anak-anak luar kawin dapat mewarisi harta warisan orang tuannya, sesuai dengan ketentuan pasal 280 KUH Perdata. Besarnya warisan yang diterima oleh anak luar kawin yang diakui, Hakim menggunakan pertimbangan hukum pasal 863 ayat 1 KUH Perdata, bahwa besarnya warisan yang diperoleh anak luar kawin adalah tergantung dari bersama-sama dengan siapakah anak luar kawin tersebut mewaris, atau bersama golongan ahli waris yang mana anak luar kawin mewaris.Akan tetapi apabila ternyata terdapat pemberian hibah wasiat kepada ahli waris ab intestato, maka hibah wasiat tersebut tidak boleh menghilangkan bagian mutlak (Legitime Portie) dari anak luar kawin sebagai ahliwaris, sesuai ketentuan pasal 913 ayat 1 KUH Perdata.

This research aims at uncovering the basis of the judge’s consideration in determining the position of the legal heir from an a born out of wedlock and in determining the amount of legal inheritance received by a son or daughter from an a born out of lock (a case study on the decision no. 554/PDT.G/2000/PN JKT PST and the decision no. 567/PDT.G/2001/PT.DKI). It is a normative, juridical research, which is completed with an empirical field research. Therefore, this research makes use of two sorts of data, i.e. primary and secondary data. The primary data are obtained by interview, while the secondary data are gained through library research by making a study on the juridical materials, which are secondary, primary and tertiary in character. All the gathered data are analyzed in a qualitative way. The research comes to a conclusion, which answers the problem that is, legal acknowledgement of a son or daughter from an unlawful marriage leads to the emergence of civil case relationship between the child and his or her father or mother. Therefore, children from an a born out of wedlock may receive inheritance from their parents according to the regulation on article 280 of the Civil Code. In determining the amount of inheritance received by the civil law-acknowledged children from an a born out of wedlock, the judge takes judicial consideration as stated on the article 863 the clause 1 of the Civil Code, which states that the amount of the inheritance received by the child from the non- marriage relationship depends on with whom he or she will share the inheritance, or with which group of heirs he or she will share the inheritance. However, if there is a gift of legacy to the heir ab intestato, the legacy should not abolish the obligatory portion (Legitime Portie) that should go to the child from an unlawful marriage as an heir, according to the statement on the article 913 the clause 1 of the Civil Code.

Kata Kunci : Hukum Waris,Anak Luar Kawin, legally acknowledged son or daughter from an a born out of wedlock, the division of inheritance.