On September 3, 2019, Sujoko Lemesan bought fuel in the form of Pertamax. Sujoko Lemesan bought at a Pertamini stall on the Batas Sumbermulya Bambanglipura Bantul road. After checking the fuel oil that he bought is less than 12 liters even though he paid for 12 liters. The first retail fuel
oil trader did not want to be held responsible for the events experienced by Sujoko Lemesan. This Legal Memorandum aims to find out whether the establishment of Pertamini is in accordance with regulations regarding downstream oil and gas activities and to find out the most appropriate legal
effort for consumers who are disadvantaged by Pertamini traders. The data used are primary and secondary data. Primary data were obtained from legislation regulation searches and secondary data were obtained from books. Analysis is done by linking legal facts with legal material so that answers are obtained for legal issues. The results of the study showed that the establishment of Pertamina was not in accordance with the regulations on downstream oil and gas activities. Appropriate legal remedy for disadvantaged consumers is to settle disputes through consumer dispute resolution bodies by means of Mediation.