When a child appears as a witness in criminal proceedings, we are talking about a category of particularly sensitive witnesses. The position and rights of children in that procedural role represent a challenge for criminal proceedings because the primacy is placed on the best interests of the child, which sometimes contradicts the rights of the defendant in the proceedings. Due to his psychophysical development, the child is always at risk of secondary victimization, therefore special rules of investigation and criminal procedure in general, try to minimize this possibility. Before a child finds himself in the role of a witness, it is necessary to assess whether he is capable of testifying, that is, whether he can understand what this duty means and what the consequences of testifying are. It is very important to assess whether the testimony will further traumatize the child and leave irreversible consequences, therefore the assessment must be done by an expert in a standardized way established by practice based on numerous scientific studies. A forensic interview is a type of interview that is used when a child is a witness to a criminal offence because its goal is to uncover the criminal offence by obtaining and revealing facts that are crucial for the court procedure. When the interview with the child is completed, it remains for the examiner to assess how credible the child's statement is, that is, whether it is true or false. Statement Validity Assessment (SVA) method or method for evaluating the validity of statements will help him in this task. It is used to reveal the truth from lies, analyzing the content of the child's oral testimony. When a child appears as a participant in the judicial system, it must adapt in many ways to the child's needs. This adjustment of the system is guided by the best interest of the child, which as a concept contains numerous rights that children have. Such a judiciary is a "Child-friendly" judiciary that, in addition to a series of procedural rights for children, also creates a coordinated network of professional, educated people who tend to work with children and young people. The procedural position of the child as a witness is theoretically on the right track, although the shortcomings of the system are visible every day in practice and there is a lot of room for progress, refinement and improvement.