The integration of artificial intelligence (AI) into criminal proceedings introduces both opportunities and challenges, also regarding the protection of defence rights. This article examines the intersection of AI, the right of defence and procedural fairness from a European perspective. It presents the hypothesis that the current deployment of AI in criminal justice systems presents more risks than benefits to defendants, particularly due to issues such as the black box problem and limited explainability of AI systems. The research explores how inadequate practice of AI systems implementation undermines key rights, including the right to information, defence preparation, legal assistance, translation and also equality of arms. The objectives include assessing whether the AI application can infringe defence rights and in what way, identifying the need for explainable AI (xAI), and proposing solutions to mitigate the risks posed by AI use in criminal trials. The methodology involves a review of European legal frameworks (regarding both defence rights standards and AI), case law, and practical examples of AI applications in criminal proceedings, supported by analysis of technical and human rights implications of AI systems like predictive analytics, natural language processing, and image recognition. Findings highlight critical gaps in regulation, emphasising the necessity for xAI to ensure transparency, effective participation, and trust in judicial processes. Recommendations include adopting a further harmonised legal framework for AI in criminal proceedings and implementing explainability measures tailored to defendants’ needs.