Introduction
In its decision dated December 25, 2025, No. E.2025/141, K.2025/274, the Constitutional Court (AYM) ruled that Articles 80/2 and 82 of the Code of Criminal Procedure (CMK), (specifically Article 80/2) are unconstitutional. This significant decision entered into force upon its publication in the Official Gazette No. 33200 dated March 18, 2026. The decision has significant implications, particularly regarding data protection law and the fate of genetic data obtained during criminal proceedings. The decision once again emphasized the principle that, given the special nature of genetic data as personal data, legal regulations in this area must include adequate safeguards.
Repealed provisions
The provisions of the Code of Criminal Procedure that were subject to review by the Constitutional Court and ruled to be repealed are as follows:
1. CCP Art. 80/2:
This paragraph provides that the results of genetic examinations conducted on samples taken pursuant to Articles 75, 76, and 78, must be immediately destroyed in the presence of the public prosecutor upon the expiration of the appeal period against a decision not to prosecute, the rejection of an appeal, or the finalization of a decision of acquittal or a decision that no penalty is warranted, and that this fact must be recorded in the minutes to be kept in the case file.
The fundamental issue with this provision is that it lacks clear regulations regarding the fate of genetic data in situations other than those specified (such as when a conviction is issued or the trial continues). This creates uncertainty regarding the duration and conditions under which genetic data may be retained and allows for broad interpretations in practice.
2. CMK Art. 82 (in relation to Art. 80/2):
This article provided that the procedures for carrying out the processes outlined in Articles 75 through 81 of the CMK would be specified in a regulation. The Constitutional Court examined Article 82, particularly regarding the delegation of procedures concerning the destruction and storage of genetic data under Article 80/2 to a regulation, and found it to be contrary to the principle of legality in matters restricting fundamental rights. This is because failing to establish the fundamental principles of critical matters—such as the collection, storage, and destruction of genetic data—which are of paramount importance for the protection of personal data, is inconsistent with the principle of the non-delegability of legislative authority guaranteed under Article 7 of the Constitution.
Reasons for annulment
The Constitutional Court based the grounds for its annulment decision on the nature of genetic data and the constitutional principles regarding the protection of personal data.
The “Special Category Personal Data” Nature of Genetic Data
The Court explicitly stated that genetic data constitutes “sensitive personal data” pursuant to Article 6 of the Personal Data Protection Law No. 6698. Such data is subject to a stricter protection regime compared to other personal data, and therefore, regulations concerning them must include higher safeguards.
Exclusion from the Scope of the KVKK and the Need for Safeguards
The Constitutional Court has stated that, pursuant to Article 28/1(d) of the KVKK, the provisions of the KVKK do not apply when personal data is processed by judicial authorities in connection with investigative, prosecutorial, judicial, or enforcement proceedings.
However, this does not mean that such data processing activities are entirely unprotected. On the contrary, safeguards regarding the protection of personal data under Article 20 of the Constitution continue to apply directly.
For this reason, the Court has emphasized that in this area where the KVKK does not apply, legal safeguards must be regulated in a clearer, more specific, and more predictable manner.
Violation of the Principle of Legality
The Court determined that Article 80/2 of the Criminal Procedure Code (CMK) fails to regulate critical matters such as the retention period for genetic data, whether it is to be destroyed, the procedures for destruction, and the data subjects’ right to request erasure.
This deficiency undermines the elements of certainty, predictability, and protection against arbitrariness under Articles 13 and 20 of the Constitution and constitutes a violation of the principle of legality. According to the Court, it is not sufficient for data processing activities that constitute an interference with fundamental rights to be regulated solely by law; such regulations must also be clear, precise, and enforceable.
Dissenting opinion analysis
The decision was adopted by a majority vote; the dissenting opinions summarized that Article 80/1 of the Criminal Procedure Code already limits data use, that retaining data serving as evidence in the case file is necessary in the event of a conviction, and that regulations regarding retention periods could be derived from general legislation. However, the majority concluded that these regulations do not provide clear and sufficient legal safeguards.
Conclusion and enforcement
The Constitutional Court’s decision to annul the provision demonstrates that the current legal framework regarding the processing of genetic data does not contain sufficient safeguards with respect to the right to the protection of personal data.
The decision emphasizes that even in judicial data processing activities falling outside the scope of the Personal Data Protection Law (KVKK), explicit legal regulations, specific retention periods, and clear destruction mechanisms are mandatory.
To prevent the legal vacuum created by the annulled provisions from violating the public interest, the Constitutional Court has decided that the annulment provisions shall enter into force nine months after their publication in the Official Gazette.
During this period, it is expected that a more comprehensive and secure legal framework will be established regarding the processing of genetic data for specific periods, depending on the nature of the decisions to be made in investigative and prosecutorial proceedings.