Purpose: As migration and separation from parents are widely recognized as important risk-factors for the mental health of adolescents, this study aims to investigate mental health problems in refugee adolescents separated from their parents compared to their accompanied peers, all living in Belgium. Methods: One thousand two hundred ninety-four-adolescents-10% of them refugee adolescents separated from both parents-completed three self-report questionnaires (Hopkins Symptoms Checklist-37A, Stressful Lite Events, and Reaction of Adolescents to Traumatic Stress) on the prevalence of traumatic experiences, anxiety, and depression symptoms, externalizing problems, and posttraumatic stress. Results: Refugee adolescents separated from both parents experienced the highest number of traumatic events compared to accompanied refugee adolescents. Risk factors influencing the development or serious mental health problems (anxiety, depression, and posttraumatic stress) are separation from parents, high number Or traumatizing events experienced, and gender. Despite the fact that refugee adolescents living only with their mother experienced more traumatizing events compared to adolescents living with both parents, they have fewer mental health problems than refugee adolescents living with their rather, Conclusions: This Study confirms the importance of the availability of parents to adolescents who have to deal with migration experiences, because separated refugee adolescents are at higher risk to experience multiple traumatic experiences and to develop severe mental health problems. Reception and care structures should provide more adequate preventive and curative interventions to these at-risk groups, and government policies should consider these adolescents primarily as "minors" rather than just "refugees." (C) 2009 Society for Adolescent Medicine. All rights reserved.