The aim of this article is to show a law tax harmonization process in a situation of a growing economic integration of member countries of European Union. In the article particular emphasis was laid on the course of a process of adapting Polish law system in the field of indirect taxes to the rules valid in the European Union. The reasoning of particular actions and negotiation moves were explained – both on Polish and European side.

The process is complex, long and difficult. However, there is a field for negotiations – The basis for the article were literature studies. Author is not the first one that is dealing with the subject. Literature in this matter is convergent in assessments and analysis of changes in case of tax harmonization. Most of authors, like Brzeziński, Głuchowski and Kosikowski [1998] or Kawecka-Wyrzykowska [2004] in their publications emphasize that the harmonization process is difficult and long. However it is inevitable to create conditions for the functioning of the common market in the EU. There are possibilities to negotiate unique solutions or transitory periods. Author concentrated on Value Added Tax (VAT) and all details concerning the process of its harmonization.