Article 20 of the Law on Registration of Trademarks and Patents of 1931 clearly recognized a priority right of a senior user of the trademark. However, the Law on Registration of Patents, Industrial Designs and Trademarks of 2007 is silent on this issue in its the trademark section. Although according to the appearance of the governing law, the criterion for legal protection of the trademark is the system of initial registration, but the current judicial precedent, contrary to the appearance of the current Law and in accordance with the content enshrined in the Paris Treaty, including Article 10 and Article 6(b) of that Convention and the supremacy of treaties over domestic laws, relying on Article 9 of the Civil Law and Article 62 of the Law on Patents, Industrial Designs and Trademarks of 2016, supports the senior user of a trademark and considers him to have acquired rights to the trademark that was used by him. And therefore, if another person at a later date registers the same or a similar trademark to describe the same goods or services, the competent court, at the request of a claimant and by verifying his previous continuous use of that trademark, relying on Article 6(3) of the Treaty of Paris and in order to prevent illegitimate commercial competition and deception of ordinary customers in determining the origin of genuine goods or services, invalidates the registered trademark in question and, according to the request of the senior user, the Trademark Registration Office is required to register that trademark in his name by following the legal formalities.