Benefiting from collective bargaining agreements by solidarity dues is a right granted to employees who work at a workplace covered by a collective bargaining agreement without being a member to a signatory labour union. On the other hand, in cases where the effective date of a collective bargaining agreement is set as a date prior to the signing date of such agreement, employees who are not members to a signatory labour union can benefit from the agreement as of the signing date at the earliest. It is alleged that this is contrary to the negative freedom of association and to the Constitution. The sentence in Article 39 of the Law no. 6356 stating that “claims for the period prior to the signing date shall be effective as of the signing date” was annulled under the Constitutional Court’s decision dated 30.12.2020 no. 57/83. Thus, for collective bargaining agreements the effective date of which is set as a date prior to the signing date thereof, it has become a topic of debate whether it is possible to benefit from such agreements as of the effective date by paying solidarity dues. In general, our study examines the conditions of benefiting from collective labour agreements by paying solidarity dues. In this extent, the reasons which the Constitutional Court relied on in its annulment decisions, and the legal problems which may arise from such annulment decision are evaluated.