Background: The focus on psychological well-being of nurses is very important for achieving high quality nursing care, because poor psychological well-being leads to lower performance and productivity of nurses. Aim of the study: To explore the effect of psychological well-being on sustainable nursing care among nurses at psychiatric hospitals. Research design: Descriptive correlation research design. Setting: The study was conducted at three hospitals; Psychiatric and neurological hospital at Assiut University, Assiut mental health hospital and Sohag mental health hospital. Sample:  Non probability convenient sample include all psychiatric nurses. Tools: Demographic characteristics data sheet, Psychological well-being scale and Quality of nursing care scale. Results: 55.0% of studied nurses have secondary school of Nursing. Also, 36.0% of nurses have 1-5 years of experience; the highest mean score for quality nursing care is about staff characteristic subscale as 23.02±5.97. While, the lowest mean score is about human oriented activities subscale as 14.75±5.56. Conclusion: Monitoring psychological well-being of nursing staff can improve productivity and quality of nursing care. Recommendation: Developing a training program to improve psychological well-being of nurses in psychiatric settings.