The Los Molles Formation is a geologic formation of Early Jurassic age, located at northern and central part of Neuquén Basin at Mendoza Shelf in Argentina. It is overlain by the Niyeu–Lajas Formation.
It is the second largest oil and gas formation in the Neuquén Basin after Vaca Muerta Formation. The Los Molles Formation is estimated to have 275 trillion cubic feet (7.8×1012 m3) of technically recoverable shale gas and 3.7 billion barrels (590,000,000 m3) of technically recoverable oil. In July 2015, the Buenos Aires Herald indicated that Pan American Energy and YPF planned to drill 46 shale gas wells in the Grupo Cuyo formation (Los Molles) over the next four years in their Lindero Atravesado drilling block, at an estimated cost of US$590 million.
Where it surfaces, the Los Molles formation has been the site of paleontological discoveries: the ichthyosaurs Chacaicosaurus and Mollesaurus. In 2017, a species of dinosaur called Isaberrysaura