Buying and selling is a legal act of transfer of ownership rights to land from the owner to another party for ever in real, clear, and cash. With the sale and purchase the seller no longer has the rights to the land. But in the Supreme Court's decision number 1979K / PDT / 2019 it was known that Samah had resold the land to Nanang Abdul Mukti and Ike Ratna Wulan which had previously been sold to Sahdan. This study aims to analyze the legal consequences of the sale and purchase of ownership rights over land which are carried out without the knowledge of landowners & the efforts to settle disputes over the sale and purchase of land rights without the knowledge of the land owner based on the decision of the Supreme Court Number 1979 K/Pdt/2019. The author uses normative legal research with a case approach and a law approach. The results showed that the legal consequence of buying and selling property rights on land without the knowledge of the land owner was that for the second time sale and purchase could be canceled and constituted an illegal act. Legal efforts to resolve disputes by filing lawsuits against the law to the Praya District Court, the Mataram High Court, to the Supreme Court by verifying that the disputed land is legitimate owned by Sahdan and the second sale and purchase is an illegal act and punish the defendants for paying the court fee for Rp. 500,000 (five hundred thousand rupiah)