The mediatization, the commercialization and the professionalization of sport have meant that in many countries the legislature had devoted special attention to this sporty sub - system. In about a century and a half of existence of modern sport in Portugal, professional sport became a social reality regulated by the state and with a legal regime that clearly differentiates from the nonprofessional sport only about 20 years ago. Young Reality undoubtedly in which three sports, football, basketball and handball proceeded successfully to the recognition of their professional competitions, though currently only football (I and II leagues) persists with such competitions. Through this investigation it can be stated that a recognized professional competition is identified by the integration of four key elements: the professional athletes, the clubs' league as the entity that manages the competition, sporting competition recognized as a professional and clubs and sports limited companies. Moreover, the dual specificity that underscores the essential elements of the legal framework of professional sport is the result of solutions both from the common law, be it labor, commercial or administrative, and from the reality closer to sports, the Sports Law.
