Objectives : The present study was conducted to determine national priorities of mental health and funded by Iranian Mental Health Research Network. The most important advantage of priority setting is effective investment and budgeting on mental health problems. Exact prioritizing increases cost-effectiveness of interventions and prevents waste of national resources. Method: Researchers from various related disciplines, health care program planners and authorities, executive managers and service providers participated in this study. In the first stage, a comprehensive list of mental health topics was prepared and classified by reviewing the literature and brain storming. In the second stage, the criteria for priority setting of topics under each field and their impacts were determined. In the third stage, using nominal group technique (NGT), 50 topics were screened and 25 topics were selected. These 25 topics were classified to smaller subjects and then expert(s) in each subject reviewed the national and international evidence of relevance and importance of each subject. Using available evidence, and by nominal group technique, priority of subjects in each field was set based on the prioritizing criteria. Results: Finally, 25 subjects were chosen. The top 10 subjects as the national mental health priorities were: three subjects from psychiatric disorders including substance dependence, depression and suicide; two subjects from mental health problems and determinants including domestic abuse and aggressive behaviors, stress and disasters; three subjects from mental health & substance use services, systems and policies including integration of mental health in primary health care, urban mental health and emergency services; and two subjects from specific populations including children and adolescents, and vulnerable women. Conclusion: The document on national priorities in mental health confirmed by main authorities in the field would, as much as possible, support and promote mental health policies and programs in the country towards the determined priorities.