Psychoanalytic interventional psychodiagnosis (PIOP) is a clinical research method that integrates psychological assessment and intervention simultaneously throughout the process, which makes it therapeutic in itself. In this sense, this book provides the reader with the theoretical foundations of this clinical practice in children with anxiety symptoms. It also presents the analysis and discussion of six clinical cases, one of which covers the entire case report. In the discussion of the cases, the reader will be able to follow how the diagnosis was made, the understanding of intrapsychic dynamics and the interventions in each psychodiagnosis. To this end, in addition to the interviews, psychometric instruments and projective techniques were used, along with interventions that were applied to both the children and their parents. The last part of this book offers a general discussion of the results achieved for each child, as well as the limitations of the method.