Law No 19.971 concerning international commercial arbitration contains rules relative to determining the law applicable to contracts, in accordance with which the parties are enabled to choose, with a high degree of autonomy, the law controlling the contract, even allowing fragmentation of the law or the choice of non-state laws. In the event that the parties do not designate the law applicable to the contract, the arbitral tribune will determine the rules of dispute in accordance with which the legislation governing them will be designated. In this sense, the regulation contained in the law on international commercial arbitration confirms the full force of the national legal code concerning autonomy in disputes as a connecting factor in contractual matters, accepted only partially by the doctrine and the jurisprudence. These circumstances permit the anticipation of possible controversies regarding the attainment of the aforementioned autonomy. Taking into account that the content of law no 19.971 corresponds, with few variations, to that of the UNCITRAL Model Law on international commercial arbitration when interpreting the first, it is pertinent to consider the history of establishment, commentaries and jurisprudence relative to the second, background that should be taken into account on fixing the meaning and the extent of its decrees.