This report is based on the actual representative epidemiological data and describes the prevalence of mental disorders in children and adolescents in the context of selected risk and protective factors. The German Health Interview and Examination Survey for Children and Adolescents (KIGGS) showed that every 7th child aged 3-17 years had noticeable mental problems. At present we are discussing a multi-factorial developmental theory for these problems. It encompasses genetic and physiological factors together with personal and individual-developmental aspects as well as psychosocial and other environmental factors which have an influence on the development and progression of mental disturbances and illnesses. The realization of the potential of existing risk and protective factors is the base for the development of preventative measures to avoid mental dysfunction. Psychosocial risk factors in children and adolescents aged 3-17 years were identified as socio-economic status, single parent households and maternal unemployment. Children and adolescents with protective factors showed fewer signs of mental problems in comparison to their fellow age group with deficits of protective factors. These results show that personal resources are the most important predictors for mental health, followed by familial and social resources.