With its decision dated 09 Aril 2014, the Turkish Constitutional Court decided to cancel article 42/1(c) of Decree Law on Protection of Trademarks Numbered 556. This decision came after the claim brought before the Constitutional Court by Istanbul 4th Civil Court of Intellectual and Industrial Rights. The Turkish Law allows any party, who has legal interest to take action, to file invalidation action against a trademark registration for non-use of the same mark, without justifiable reason, within five consecutive years after the registration. The local Judge brought the action before Constitutional Court arguing that although the local law allows invalidation of non-used mark, the international regulations provide cancellation of non-used mark, not invalidation. The most significant difference between invalidation and cancellation is when the effect of the decision starts: in cancellation it starts from the date the registration was made, in invalidation it starts from the date the cancellation decision is announced. On the other hand, the other side of the problem lies with the trademark regulation effective in Turkey: Decree Law. The Turkish Constitution clearly states that property rights cannot be limited with anything but law; thus decree laws cannot limit property rights. The local Court was of the view that the cancellation of a trademark from the date it was registered is severe infringement of property right. The Turkish Constitutional Court adopted the approach of the local Judge and decided the cancellation of this article. With this decision, it is no longer possible to seek the invalidation of non-used mark in Turkey. However, it is still possible to cancel non-used mark because article 14 of the Decree Law that allows cancellation of non-used marks is still in effect.