Background: Nurses' COVID-19 knowledge in primary health care is vital for managing the pandemic, including prevention, detection, and patient education. As we know, the danger of Covid-19 is not limited to workers in health centers only, but it may develop and spread to all members of society due to the lack of knowledge of health workers about methods of prevention and protection from this disease. Objective: This study assesses nurses' COVID-19 knowledge at primary healthcare centers to control the spread of the virus. Methods: A descriptive study was conducted on the knowledge of nurses about COVID-19 at PHCs in Al-Najaf city. The study spanned from March to the end of July 2023. A total of 122 samples were collected from nine PHCs in AL-Najaf quarters. using a two-part questionnaire. The first part consisted of demographic information (6 items), and the second part involved scale questions to assess nurses' knowledge (35 items). Results: The study revealed that more than half of the nurses possess moderate knowledge (53.28%), while less than half demonstrated good knowledge (40.72%). It was found that demographic information does not correlate with nurses' knowledge of COVID-19., with the exception of variations across primary healthcare centers. Conclusion: The majority of nurses working in health centers have a moderate level of knowledge about COVID-19.