Background A comprehensive assessment is essential to contemporary practice in child and adolescent mental health. In addition to determining diagnosis and management, it is seen as important for clinical engagement and forming a therapeutic relationship. However, there has been little research on the processes which occur during this interaction, particularly in first assessments. Method Twenty‐eight naturally occurring child mental health initial assessments were video recorded and subjected to the basic principles of the conversation analytic method. Results Several processes were identified in a typical child and adolescent mental health assessment. These included introductions, reasons for attendance, problem presentation, decision‐making and session closure. Conclusions Initial assessments provide a platform for all future engagement with services and an understanding of the processes occurring within this setting is important for the eventual outcomes, particularly in respect to new ways of working such as the Choice and Partnership Approach (CAPA).