Background: Psycho education is among the most effective of the evidence-based practices that have emerged in both clinical trials and community settings, it showed weighed excellent benefits when administered to those with bipolar affective disorders, reducing both re-hospitalization rates and decreasing the number of days a person spends in the hospital .Aim: The study aim at assessing the effectiveness of psycho-education for family caregivers of patients with bipolar affective disorders at El-Tegani El-Mahi psychiatric teaching Hospital, Sudan, October 2017 to March 2018.Methods: This study is a quasi-experimental pre/post-tests hospital based, the sample consisted of (73) family caregivers who were all available at the hospital during the period of the data collection. They selected by total cover of all family caregivers close with patients. Data was collected by the use of Structured questionnaire to assess the family caregiver knowledge by likert scale, data was analyzed by Statistical Package for Social Science (SPSS) version 20.and presented figure and tables. Results: the study revealed that the mean score of knowledge before the psycho-education: 28.9. Their knowledge is poor according to compared with the overall mean knowledge post psycho-education were 73.0 with (p.value=,000).Conclusion & recommendation: Psycho education highly significance and improved the knowledge among the family caregivers of the patients with Bipolar Affective Disorders, the recommended establishment of collaborative relationship with families and educational interventions by the nurse under the guidance of the Psychiatric Hospital.