This article analyse the choice of law process, especially in absence of choice of law by the parties with regard to the three main aspects or issues of applicable laws, namely, the law applicable to arbitration agreements, applicable law to the arbitration procedure and the applicable law to the merits of the parties’ dispute. In international commercial arbitration parties or the subject-matter have connection with different legal systems and this is the reason why the choice of law issue is of a great importance, and it could be less problematic issue if the parties have designated the law to govern the issues mentioned above, but the problem becomes greater when the parties have not chosen the applicable law. After this, it is for the arbitral tribunal to decide upon the applicable law to one of the issues, and for this reason the first part of this article discusses the authority or the discretion of the arbitrators in the determination of the applicable law in absence of chose of law agreements. More importance in this article is dedicated to the choice of substantive law or the choice of law governing the merits of the parties’ dispute, because it is a bit more complex than two other aspects of the applicable laws in international. The each aspects of applicable laws are treated in the article, with a special emphasis in the methodology and existing approaches in the choice of law process. The issue of choice of law in international arbitration is regulated by the most recognized international conventions, institutional rules and almost in all national arbitration statutes. As we will see here the choice of law issue it is regulated differently by the abovementioned legal instruments and we will analyse that what approaches they suggest that the arbitrator must follow to select the proper law. Another characteristic of all this issue is the application of the non-national rules and general principles of law, with a variety of sources, and in this article we will have an overview of the application of these rule. The aim of the arbitration is to resolve a dispute and to produce an award which it would be enforceable, and the relating to the enforceability of the award the arbitrators have the duty that to choose the law which would give effect to the arbitration agreements, so the mandatory provisions could limit the choice of law in international commercial arbitration and this issue is a part of this article. Keywords: choice of law, absence of agreement, arbitrators, applicable law, approaches