ENFrom a financial perspective transfer pricing is probably the most important tax issue in the world. The number of inter-company transactions is rapidly increasing. As the tax rates in different countries vary significant, companies, especially multinational ones, in order to minimize their payable taxes often set the transfer prices that are not in line with the arm's length principle. Thus, the governments of many economically developed countries implemented the arm's length principle in the domestic tax legislation. In 2004 the arm's length principle (the Order of the Minister of Finance No. IK-123) was regularized in Lithuania. Under this Order all the transactions between associated parties have to be concluded at the market price, i.e. the transfer prices should be in line with the arm's length principle. In order to set the arm's length transfer prices, the Lithuanian tax payers have to apply the following transfer pricing methods: comparable uncontrolled price method; resale price or cost plus method; profit split or transactional net margin method. Applying all the aforementioned transfer pricing methods the transfer prices are set based on the uncontrolled comparable data, e.g. the prices set in the transactions concluded between unrelated parties.However, in the oligopolistic and monopolistic markets when a company has some market power it may influence the prices set to unrelated parties making impact to the transfer pricing as well. Therefore, in such case, the different comparable data should be taken or different transfer pricing approaches applied.