Illegitimate children are children born to their parents without a legally valid marriage bond. In this thesis the author discusses civil law regulations and the decision of the Constitutional Court (MK) regarding the protection of illegitimate children using normative legal methods. Legislation explains that illegitimate children are said to be illegitimate children; civil relationship with mother only. However, after the issuance of the Constitutional Court decision Number 46/PUU-VIII/2010, it further strengthened its legal position by stating that illegitimate children can be recognized as having a civil relationship with their biological father if it is legally proven in law. legal eyes such as DNA testing. This decision drew a variety of responses, ranging from appreciation for the protection of children's rights to concerns about its impact on social norms. The results of the research, after the Constitutional Court decision was issued, stated that there would be a civil relationship between the child and his father if it could be legally proven such as a DNA test. This can be seen as legal protection for the civil rights of illegitimate children who have their biological father.