This study reports on the first large-scale investigation of mental health in Cambodia. A randomized sample of 2690 adults from nine provinces was interviewed about mental health and mental disorders, addictive and violent behaviours, suicidal tendency, traumatic events, and culturally influenced symptoms related to mental health. In addition, the Harvard-Trauma Questionnaire (HTQ), the Hopkins Symptoms Checklist (HSCL-25) and the Cambodian Addendum of Culturally Sensitive Items (now C-SSI) were administered to all respondents. Results indicate high rates of children ́s problems, especially aggressive behaviour in the families, child abuse, suicide and suicide attempts.