This study holds that the major success of antitrust legislation in Chile thus far to date, a pioneer in this respect in Latin America, supports the idea that only a structural change oriented more towards the market as the allocator of resources makes the implementation of antitrust legislation viable. On the basis of a vast analysis of the jurisprudence of the antitrust commissions in Chile since their inception in 1973 through 1993 indicates that the ample nature of Chilean legislation in this field has proven to be adequate since the antitrust commissions can interpret the spirit of the law. Thus, only jurisprudence defines the scope of those legal rules. Consequently, in the opinion of the author, rigid standards must not be set in this matter under the pretext of delimiting the action of the law. Although they offer predictability, they can seriously affect the actions of companies that are endeavoring to increase efficiency.