Background: The nurse manager is one of the nurses who has authority to implement a nursing management system in a nursing organization to achieve goals based on the input, process and output stages, whether the Covid-19 pandemic has positive and negative impacts on the implementation of the nursing management system. Nursing management is a form of coordination and integration in achieving nursing care and nursing services. Purpose: The purpose of this study is to explore the experience of nurse managers in implementing nursing management system in the COVID-19 wards. Methods: This study used a phenomenological descriptive design and in-depth interview data collection methods. Furthermore, the implementation of this research was carried out in 10 hospitals in North Sumatera, especially Medan City, Deli Serdang Regency and Serdang Bedagai Regency. The participants involved in this study were 20 participants and used the Collaizzi data analysis method. Results: This study revealed 7 themes related to the experience of nurse managers running a nursing management system in the COVID-19 treatment room; (1) Requires extra high discipline to carry out nursing management functions, (2) There is a psychological disorder for nurse manager to carry out nursing management, (3) Requires moral and material support in carrying out their duties, (4) Performs various efforts to disseminate information on nursing care management systems, (5) Experiences more benefits in implementing nursing management in the COVID-19 ward, (6) Faces complicated obstacles in carrying out nursing management, and (7) Has high expectations in carrying out increasingly complex management functions. Conclusion: From the themes above, the researcher concludes that the nursing management system in the COVID-19 treatment room involves psychological feelings, requires extra self-preparation, requires support from all parties in providing nursing care, improving nursing services to the fullest and can develop the concept of nursing management system during a pandemic.