This chapter outlines the assessment process for adolescents being considered for intensive CBT-E. A collaborative, patient-centred approach is emphasized throughout. Assessment begins with a one-to-one meeting with the adolescent to build trust, explore their attitude towards treatment, and assess the nature and severity of their eating disorder. Based on this, the indication for intensive CBT-E is considered. A central component of the assessment is introducing the psychological model that underpins CBT-E, in contrast to the disease model, which views eating disorders as a disease requiring external control. The psychological model promotes insight, autonomy, and collaboration, highlighting the adolescent’s active role in understanding and addressing their difficulties. For this reason, patients are invited to participate in a preparation phase, consisting of four to six sessions. The goal is to develop a provisional personal formulation and support the adolescent in deciding whether to proceed with treatment. This phase does not aim to initiate behavioural change, but to enhance engagement and ensure that treatment begins only with the patient’s informed agreement.