During the execution of its power, the tax administrator collects a large amount of information on taxpayers, be it on natural persons, legal entities or other legal arrangements. The article focuses on for what purpose the tax administrator collects the information and whether they are bound by this purpose, i.e. whether this information could be used in a different manner other than tax administration and whether they can use it only for the tax administration in the relation to which it was obtained or if they could be used in the administration of the taxes in general.