Certain developments that occurred consecutively in the field of Turkish Trademark Law have rendered the outcome of the violation of the obligation to use a trademark, which exists since the Decree No.556 on Protection of Trademarks (the "Trademark Decree"), debatable. As is known, the non-use of a trademark for a period of five years leads to the sanction of revocation pursuant to the Trademark Decree art. 14 and the Industrial Property Law art. 9. The Paris Convention and TRIPS Agreement also regulate this sanction optionally. The problem at hand arose due to a gap of mere four days between the revocation of the Trademark Decree Art. 14 via Constitutional Court decision, and the date when IPL came into force and said provision was re-enacted through IPL art. 9. As a result of the Constitutional Court's decision, as of 06.01.2017, the obligation to use the trademark cannot be imposed on the proprietor. As a consequence of the principle of non-retroactivity of laws, IPL art. 9 imposes an obligation to use beginning from the enforcement date of this law. Consequently, since there was no obligation to use for proprietor on the enforcement date, the obligation to use would have commenced on 10.01.2017. This situation is in favor of proprietors who seek to obtain rights based on the trademark they do not use, however to the detriment of an aggrieved party. Although the scholars have different opinions and solution proposals, these proposals seem to be inadequate, unless a provision governing enforcement is added to IPL and it is stated that the five-year period will be calculated considering the period before the enforcement date of the IPL.