BACKGROUND: Nurses represent the largest section of the health-care workforce, and lack of sleep has an adverse influence on them, particularly during pandemics such as coronavirus disease 2019 (COVID-19). It causes not only health problem but also poor work results and an increased risk of medical errors. AIM: The goal of the study was to determine the prevalence of poor sleep quality among nurses during COVID-19 outbreaks. MATERIALS AND METHODS: A cross-sectional analysis was conducted among a group of nurses in the Al-Madinah region of Saudi Arabia at the National Guard Health Affairs in 2020 (1st year of the COVID-19 crisis). Data were collected using a validated questionnaire with two sections: Sociodemographic data such as age, nationality, family status, gender, and the Pittsburgh Sleep Quality Index. RESULTS: There were 238 nurses in the report. 37.8% of them were found to be between the ages of 31 and 35, while 24.4% were under the age of 30. The nurses were mostly female (84%). Sleep latency, sleep disruption, overall subjective sleep quality, and sleep length were the most widely identified sleep problems. Sixty-six percent of the nurses said they had a poor night’s sleep. None of the demographic variables analyzed had a significant relationship with overall sleep quality. CONCLUSION: Majority of nurses working at the National Guard Health Affairs and primary health-care centers in Al-Medina, Saudi Arabia, experience poor sleep quality, during the 1st year of COVID-19 crisis regardless of their demographic characteristics.