This monograph discusses the concept, consistency and the existing rules about Local Content; describes the Brazilian market of Oil & Gas; the performance of Brazilian Suppliers; and the development of the Brazilian Oil & Gas Industry. This paper presents government policies developed in some countries to increase the domestic content and in some cases the regulation of foreign direct investment. The Local Content works as not to exclude potential Brazilian Suppliers from the competition providing equal opportunities to local suppliers in order to achieve the substitution of importations. Actually, it was created as a mandatory clause in the concession agreements and it is one of judgment criterion in the ANP’s auctions. This text shows an unpublished general overview of the local content presenting suggestions, matters, formulas, calculation system and legal conflicts of Local Content. The rules and the desire of fomenting the domestic content in Brazil are strongly discussed in this paper.