Reason which is based on the desire of human to know and therefore, as a concept, goes back to the very old times has become a fundamental right in due course. The right to a reasoned judgement is currently considered as an element of the right to a fair trial. As a matter of fact, this right is protected in our judicial system with the legislation and practices in addition to the protection ensured by the European Court of Human Rights (ECHR) case law, which is based on Article 6 of the European Convention of Human Rights. At this point, it is a critical phase to introduce the individual application to the Constitutional Court pursuant to a Constitutional amendment. In our study, the right to a reasoned judgement is primarily addressed with the ideational foundations of the reason and the relevant ECHR case-law is also examined. Subsequently, the practices regarding the essentiality of reason under our law are handled within the framework of the Constitution and codes as well as the Constitutional Court's and the appeal courts' judgments and an assessment is carried out accordingly.