The right to a trial within a reasonable time is of immense importance in the realization of a fair and legal court procedure. This also applies to criminal proceedings. The paper explains the concept of the right to a trial within a reasonable time, and in the introductory part a special emphasis is placed on the convention aspect and the purpose of this right. As the ECtHR imposes on member states the obligation to establish an effective legal remedy for the protection of that right, Croatia also has such a legal remedy - a request for the protection of the right to a trial within a reasonable time. The development of that legal remedy is critically described, as well as the legal framework concerning the remedy, and in that part, the conclusion reached is that this form of protection is not optimal. Then, using statistical information, a more comprehensive picture of the situation of the protection of the right to a trial within a reasonable time in justice system was provided. The fourth part analyzed the recent practice of the ECtHR in criminal cases in which the Court decided on the violation of the right to a trial within a reasonable time. Finally, the practice of the Constitutional Court of the Republic of Croatia is presented and analyzed in comparison with the practice of the ECtHR. The conclusion is that the Constitutional Court of the Republic of Croatia should be more diligent in deciding on these violations so that the legal standard for the protection of this right is as high as possible and aligned with the practice of the ECtHR.