The increase on the amount of business transactions, due to a higher facility to access and to enter international markets, additionally to the decrease of the barriers to international trading, derived from globalization, demand consistent international agreements that reflect the duties and needs of countries which belong to international trade. Therefore, international treaties are increasingly present in the application of international business operations. The tax system of each signatory State is a matter of extreme relevance to such agreements. Certain characteristics in the Law area are essential to understand and avoid double taxation. This paper seeks to a study of the treaties that prevent it. To this end, it presents a study of the OECD Model Convention demonstrating its main articles and exposing the relations between it and the Brazilian and Swedish international tax agreement; provides a clarification of the reception of international treaties process in Brazil; and exposes the legislative particularities among Swedish-Brazilian agreement. Moreover to understand how the courts have been acting in relation to this issue, this paperexposes an analysis using an application of the Convention in practice, by a financial simulation.