European studies revealed that mental disorders among children living in institutional care are an important social problem. In the UK, 96% of children aged 13–17 living in institutions met criteria of mental disorders. In Germany, among children aged 4–18 living in institutions it was 59.9%. The purpose of an epidemiological study conducted in the Department of Child and Adolescent Psychiatry in the Medical University of Warsaw was to determine the prevalence of psychiatric disorders among children and adolescents aged 11–18 years, located in Warsaw residential care (children homes). It was the first Polish epidemiological study carried on this population. The study consisted of two stages. One hundred and forty one children from 11 institutions participated. Reference group was 103 children from Warsaw schools. In the first stage children and adolescents completed the Youth Self-Report (YSR). In the second stage respondents whose score in any of the individual YSR scales was in the clinical range were examined individually using K-SADS-PL diagnostic interview, in order to make a diagnosis of mental disorders. Also, the study carried out in Warsaw children homes proved that mental disorders can be diagnosed in more than half of the children and adolescents. This is an important information that can not be overlooked in the debate about the proper mental health care system and psychological help for children and youth in Poland. In the speech results of epidemiological studies on the prevalence of mental disorders among children and adolescents resident in Warsaw residential care(children homes) will be presented. Therapeutic needs of the children and adolescents and recommendations of possible ways of meeting those needs will be discussed based on the conclusions of the study.