The digital transformation of criminal justice systems, particularly the growing application of artificial intelligence (AI) in evidence analysis and judicial decision-support processes, has raised significant challenges at both national and international levels regarding compliance with fair trial guarantees and the protection of defendants’ rights. Focusing on the Iranian legal system and informed by international criminal law and human rights standards, this study examines the compatibility of AI-driven judicial practices with fundamental principles of criminal procedure, including the presumption of innocence and the Islamic legal doctrine of Dar’a (the principle of avoiding criminal punishment in cases of doubt). The study aims to explore the analytical capacities of AI in evaluating evidence, enhancing judicial consistency, and reducing human error, while also identifying the legal and ethical challenges associated with its deployment, such as algorithmic transparency, data bias, criminal liability, and regulatory oversight requirements. Employing a descriptive-analytical and comparative methodology, the research draws upon legal instruments, judicial practices, and scholarly literature in criminal law, technology law, and international law. The findings indicate that AI has the potential to strengthen the coherence of judicial decisions and contribute to the protection of defendants’ rights. However, in the absence of effective oversight mechanisms and adequate explainability safeguards, its use may increase the risk of discrimination and violations of due process and fair trial principles. Accordingly, the legitimate integration of AI into criminal justice systems requires the development of comprehensive legal frameworks aligned with domestic legal principles and international human rights standards.