In regards to this subject it detaches Rosseti well, oligopoly is a market form where few salesmen exist, ahead of a great number of purchasers, of form that the salesmen exert great control on the prices of products (2003; p.158). Three forms of oligopoly exist: monopoly, cartel and holding. In the monopolies the companies open hand of its independence, but without losing its autonomy, in order to join itself forming an only organization dominating the market in offers of goods and services and to suppress the free competition; Cartel is an implicit agreement or explicit it enters the competitors for setting of prices, distribution of performance markets and of customers, generally in the cartels the products of the companies are homogeneous, in this type of oligopoly are eliminated the competition with consequent increase of prices and having diminished the possibility of choice of the consumer, becoming the more expensive goods and/or services and even unavailable; Holdings, is created a company, this here possesss the biggest number of action, to manage a group of them that they had been joined with intention to promote the domain of the market, offers, the prices of the goods and/or services. These types of oligopoly are considered crimes in all the countries that possess antitrust legislation, and Brazil is one of them, that it regulates these practical in its legislation through the laws to follow: Law 4,137/62 – Law of the abuse of the economic power; Law 7,347/85 – Interest diffuse; Law 8,158/91 – Economic defense (antitrust); Law 8,137/90 – Crimes against order tax, economic and relations of consumption; Law 8,884/94 – CADE (antitrust); Law 9,021/95 CADE; Law 9,470/97 – It modifies 8.884/94; Law 10,149/00 – It modifies 8.884/94; Law 10,843/04 – It modifies 8.884/94. 3. Principles of the Economic Order Questions about the economic order in Brazil they start to acquire legal dimension with the Great Letter of 1946, in its art.