Researchers suppose that there live over twenty thousand unregistered children in Korea. It is impossible to statistically figure out the exact numbers of undocumented immigrant children in Korea for they are not registered. In accordance with Article 6 of the Korean Constitution, ‘Conventions concluded and promulgated by the Constitution and generally approved international laws have the same effect as domestic laws’. Therefore, Undocumented Immigrant Children must have the human rights and constitutional rights so that Convention on the Rights of the Child was enforced in 1991 in the Country. Due to the limit of Immigration Control Act and the Family Relations Registration Act related to birth registration; however, children who cannot register their births are at risk of illegalities and abuse while being born and raised in Korea. Korean government has imported overseas people for the population and labor policy, but ignored their lives as human being. By revising Article 84 of the Immigration Control Act in 2012, the obligation of public officials to notify illegal facts was removed, and even unregistered children can receive education. In 2021, the Ministry of Justice implemented the “conditional relief measures for illegal children born in Korea”, but this is temporary and limited actions. In order to protect children’s human rights and solve the population problem that has lead an aging society with low birth rates, legal actions should be taken for the birth registration and stable stay of undocumented children in Korea.