Land is a natural resource that is freely given to humans by God Almighty. All human activities are carried out on the land. In Indonesia, the provisions regarding land are regulated in Law no. 5 of 1960 concerning Basic Regulations on Agrarian Principles which has the main objective of controlling land for the prosperity of the community. Land control over land must have a basis for its rights, hence control over land must be legal. Land registration must be carried out to obtain legal certainty. However, in practice there are still frequent disputes between land ownership, including double certificates. In this study there are 2 formulations of the problem 1. How is legal certainty of land ownership viewed in terms of national land law? 2. How is the analysis of the judge's legal considerations in the decision No. 18/Pdt.G/2018/ PN Nab, in conjunction with decision No. 94/PDT/2018/ PT JAP in conjunction with the Supreme Court's decision No. 3559 K/Pdt/2019 in the plaintiff's land ownership in the event that there are multiple certificates?. This thesis uses normative legal research by studying national land law. From the results of the research, the authors conclude that there is legal certainty in Indonesia in the form of certificates as a strong evidence and the provisions of Article 32 of government regulation No.24 of 1997 and the judge's decision. 18/Pdt.G/2018/ PN Nab juncto Decision No. 94/PDT/2018/ PT JAP in conjunction with Supreme Court Decision No. 3559 K/Pdt/2019 is correct.