Objective: This randomized controlled trial evaluated the effectiveness of a group psycho-educational program on caregivers of mental disorders. Hundred family caregivers of patients with Schizophrenia and mood disorders that attending in Noor hospital, affiliated to Isfahan Behavioral Sciences Research Center, were the study population. In this study, Caregiver is one who is a member of the family (parents, children,..) and has the most frequent contact with the patients, helps to support the patient financially, has most frequently been collateral in the patients' treatment . The psycho-educational intervention that was used in this research consisted of four consecutive weekly sessions providing information about patients disorder process, teaching symptom management, teaching caregiver self care, discussing psychosocial issues, providing mutual support to one another, teaching them to monitor their own feelings, teaching coping skills and problem solving and it was offered in a group format. It was used because group education programs have been widely recommended as a valuable strategy to deliver support and information to family caregivers. The program followed up for a period of 3 months and caregiver burden was assessed by using the Zarit Burden Interview (ZBI).