The article analyzes Pemex’s investment policy for the period 1980-2019, based on the management of other oil companies. The central question is whether in the last four decades, it has been convenient for Pemex to be specialized in oil extraction, while other companies focused on the comprehensive development of the supply chain. The answer is negative. The sale of crude oil and the abandonment of refining made Mexico a net importer of fuels, a trend, which, today, is seeking to be reversed, in an environment of a high fiscal burden and high indebtedness of the company.