Energy sector has been one of priorities of the EU regarding competition law. As stated in introduction, fair competition is applied to the gas sector through application of the Articles 101 and 102 TFEU when the actions of gas companies make it applicable. On the other hand, it is also included to the market through sector specific legislation. It has been rather successful at imposing competition rules to gas sector both through case law, as through sector specific legislation, such as energy legislative packages. But the market of gas is not completely liberalized yet, especially not in the Central European countries. One of the reasons is that in the whole European Union, there are seven big energy utilities that are present in several Member States. Most of them are cooperating with each other, mainly through mergers and acquisitions and trying to strengthen their position in the market, which sometimes presents a violation of the provisions of TFEU. Instead, the companies should, according to the Commission work in a way that is compatible with the EU law. A rather common action that was seen from the companies’ side is joint marketing of gas, that Commission also investigated. In those cases it was deciding according to the Article 101(1) TFEU and it found two variations of violation of the abovementioned article. In the Corrib case there was an obvious territorial sales restriction within the production and sales of gas, in a form of horizontal agreements. The latter are one of the agreements that fall within the scope of provisions of Article 101(1) TFEU, and are therefore not permitted. In the GFU case the joint selling of gas was happening in a form of cartel, which is one of the hardcore restriction of the Article 101(1) TFEU and therefore the Commission once again proved that it is exercising its competence in a way of protecting fair competition that leads towards a fully competitive internal market of gas. Another hardcore restriction that appeared in the investigations is also the actions in DUC case where the Commission interpreted the collective negotiation of the DUC members as joint coordination of sales that restricted competition. In this case the Commission did not allow the joint marketing to be interpreted as a block exemption and therefore did not allow it, which shows the Commission’s strong stand against hardcore restrictions of Article 101 TFEU. Another type of restrictive actions that the Commission did not tolerate and therefor investigated is destination clauses. Therefore the Commission was looking upon the vertical restrictions on commercial freedom of gas sales. Because of damaging effects of vertical restrictions, was the Commission acting rather strict when deciding upon the cases. In the GDF it found that the two clauses that restricted the territory where ENI and ENEL were able to resell the gas caused partitioning of the market. Therefore it did not allow to impose an exemption of the prohibition of Article 101 TFEU. Commission was also showing its strong position on not allowing destination clauses in the Gazprom cases. But although Commission showed its relatively strong position in the protection of fair competition in the gas markets, the gas utilities were still violating the EU rule on competition. Therefore the Commission investigated more cases regarding horizontal restriction, such as in the case of E.ON Ruhrgas and GDF. The Commission showed its strong stand and it looked into any types of arrangements that could distort competition, which is in accordance with the interpretation of Article 101 TFEU. Additionally, in the case of ENI group the Commission applied sector specific legislation and showed that the companies need to consider Gas Directive and Regulations as well when acting on the gas market. Commission’s work on progression of fair competition in gas market is constant. In the last round of investigation it investigated that was, first of all abusing its dominant position that affected interstate trade in the five Central and Eastern European countries and therefore violated the prohibition of Article 102 TFEU. Second of all, it imposed territorial restrictions that might result in unfair prices of gas that clearly violates the provisions of Article 101 TFEU. Therefore it is important that the Commission recognized the violation by Gazprom and investigated on the case. But it is not just upon the gas companies to change their businesses, it is also upon the Member States to impose the rules that help providing a fully liberalized market in the States and therefore provide a free choice for the consumers. As seen, one of the tools to achieve it is trading hubs. They have consequences for fair competition in the gas market to the extend that there is no long-term obligation for the buyers to buy a certain amount of gas in a long term. If we i.e. take a look at the NBP hub, we can see that 70% of the gas sold is over the Counter volumes and the price is not oil indexed, but it reflects commodity price with no geographic differentials. Developed trading hubs within the EU would bring a very liberalized financial market of gas trade that would be within the policy of the EU regarding fair competition. As seen at the two advanced hubs, the price of gas is not prone to oil prices, but is based on the economical situation of supply and demand. As the sales of gas are anonymous, there is less possibility for restrictive agreements between companies, which brings the situation a step closer to the fully liberalized market. Another aspect of gas market that plays an important role at liberalization is access to transmission system in a form of Third Party Access that can be plausible for both the owner, and the users of pipelines that would be able to transfer their gas through pipelines that are already built and not have enormous expenses in building their own pipelines, especially if the gas providers are smaller entities. Another important aspect regarding transmission systems is also making transmission system operators independent from gas companies. As that was not fully achieved after the second energy legislative package, it is important that both the Member States and the EU develop and supervise the development of unbundling in the markets. Central European countries will in the near future have a lot of work at achieving fully developed market in terms of fair competition and liberalization. On the other hand, the European Commission might need to help them in order to become less dependent from the Russian gas imports. That is important because, as seen in example of Hungary, because of the dominance of the Russian gas there has been a lack of competition. But some of the Central European countries are slowly moving towards liberalized gas market with various competitors present. One example is Czech Republic, where there were recently imposed national rules on unbundling, that are implementing provisions of the Third GasDirective. The regulation imposed an Independent Operator and it unbundled distributor of gas from the TSOs, gas trading companies and storage operators, which will should lead to a better choice for customers and more fair prices. Another aspect of market liberalization that will in the future play a relevant role is also that the process is being controlled by the Commission, CJEU and National Competition Authorities. The first two were involved in the case of regulation of Polish regulation of natural gas prices and showed that the supervision of the development of the fully-competitive, liberalized market. National Competition Authority of the Republic of Slovenia on the other hand, showed its big involvement on supervision of imposing of fair market and gas trade. It investigated the biggest national gas provider several times, on the terms of merger control, as also on abuse of dominant position and showed its strong stand regarding competition protection. Achieving a state of a fully liberalised market with fair competition rules and totally liberalised market of gas trade is a lengthy and complicated procedure. Because of all the aspects that need to be considered and 27 different situations of the market of gas in the EU, the common internal market is a very high goal to be achieved, but not impossible. As long as the Member States cooperate with the Commission and supervise the acts of the companies in accordance with the Energy Legislative package and with the Articles 101 and 102 TFEU, the tendency will go towards the achievemnt of fully competitive internal market.