The aim of the study was to investigate the extent of social anxiety in different mental disorders. A total of 341 patients aged 7-18 years participated in the study. To measure social anxiety, the German version (SPAIK) of the Social Phobia and Anxiety Inventory for Children (SPAI-C) was used. Subgroups were built dependent on mental disorders. A total score above 20, which was assumed to indicate social anxiety, was observed in children with selective mutism (n = 9; M = 22.68; SD = 11.29) and in children with Asperger's Syndrome (n = 7; M = 20.77; SD = 13.77). Patients who had the following mental disorders also showed a higher total score of social anxiety: obsessive-compulsive disorder, anorexia nervosa, schizophrenia, depression and conduct disorder. In none of these disorders, however, did the mean total score exceed the cut-off of 20.