According to article 13 of the law “on the management of free commercial-industrial zones” , ratified in 1993, legal and natural entities who are engaged in performing economic activities in free zones are exempted from paying taxation of their economic activities for 15 years (from the date of beginning their activity). Nowadays, some companies establish their residence or a branch in free zones while a great number of their economic activities is carried out outside free zones ( in Tehran or other industrial cities). They do so to take advantage of the above-mentioned article and be exempted from paying their taxes. They try to pretend that their whole income is obtained inside the free zone which enables them to avoid paying their taxes. Meanwhile, it is probable that the representatives of foreign sellers hold a branch in a free zone and a huge amount of their sales takes place outside free zones through marketing and advertising in the media and regard such sales to have happened outside free zones. It is worth mentioning that according to article 13 of the law “on the management of free commercial-industrial zones” , ratified in 1993, tax exemption is dedicated to those economic activities that were exclusively carried out in free zones, regardless of company residence or the address of branch or company office which is located in free zones. So, only the income which originates from economic activities taking place inside free zones are exempted from tax payment and the income of those economic activities which take place between free zones and other districts will be included in the tax exemption as well.