22q11.2 deletion syndrome is the most common interstitial deletion syndrome in humans. Patients with this syndrome can show a variety of somatic symptoms, especially characteristic facial abnormalities, heart defects, thymic hypo- or aplasia and velopharyngeal dysfunction with or without cleft palate. Disturbancies in motor, language, cognitive and social development are typical, as well as psychiatric disorders. Psychiatric disorders in children and adolescents are mostly attention-deficit/hyperactivity disorder, affective disorders, and autism spectrum problems. Schizophrenia in adults seems to be caused by 22q11.2 deletion in about 2% of all patients. We review current knowledge about etiology, physical features, developmental aspects and psychiatric comorbidity in 22q11.2 deletion syndrome as well as possible therapeutic interventions. Clinical criteria for genetic examinations on 22q11.2 deletion in children and adolescents with psychiatric disorders are defined. Until now 22q11.2 deletion is underdiagnosed in this population--despite of its clinical relevance.