The paper deals with a legal institutes that are available to tax authorities and courts in the fight against tax avoidance. It explains the difference between legal and illegal tax avoidance and measures that can be applied for the prevention of tax avoidance. This paper explains tax planning as an effective means of reducing tax burden. Techniques and strategies of tax planning are mentioned together with holding companies as one of the most important instances in the area of tax planning. Furthermore, the paper describes action of „economic approach principle“ provided for in Article 11. of the General Tax Act as important tax regulation. The meaning of the provision of Article 12. of the General Tax Act on sham transaction is also analysed. It explains sham transactions in the civil law and in the tax law sense. After that, the paper deals with General Anti Avoidance Rule which is introduced in our Corporate Income Tax Act in article 5. a. The meaning, the way of applying and the critical approach to the mentioned rule are described. And last, some special anti avoidance rules are quoted and explained. It will be about rules of thin capitalization, transfer pricing and withholding tax.