INTRODUCTION: The coronavirus pandemic (COVID-19) is an unprecedented global health crisis with emotional and physical impact on health care workers. OBJECTIVE: The purpose of this study was to investigate the levels of fatigue and burnout in nursing staff during the pandemic. METHODS: The present study involved nursing staff from hospitals in Greece in February 2021, who completed the Fatigue (FAS) and Burnout (CBI) questionnaires. Gender, age, years of work experience, workplace (COVID-19 or non-COVID-19 wards) and SARS-CoV-2 infection status were recorded. RESULTS: The sample included 593 women and 108 men, with a mean age ± SD: 42.9 ± 9.9 years and 18.14 ± 10.8 years work experience. Slightly more than half, (367, 52.4%) worked in COVID-19 departments. Fifty-six (8%) tested positive for SARS-CoV-2 and 14 of them needed to be treated. The mean ± SD FAS and CBI scores were 25.6 ± 7.4 and 46.9 ± 18.8, respectively (67.9% and 42.9% had scores suggestive of fatigue and burnout, respectively). Women showed higher values in both scales (p < 0.01). Subjects working in COVID-19 wards scored significantly higher on both the FAS and CBI scales; they were also younger and with less work experience (p < 0.01). Staff treated for COVID-19 scored higher on the burnout scale (p < 0.01) than the uninfected staff. Fatigue showed a strong positive correlation with burnout (p < 0.01, r = 0.70). Stepwise multiple regression showed that the variation of fatigue was explained by 47.0% and 6.1% by the scores on the subscales of personal and work-related burnout, respectively. CONCLUSION: In conclusion, high rates of fatigue and burnout were found in the studied population. Nurses working with COVID-19 patients had higher rates of fatigue and burnout compared to those working elsewhere. There was a strong positive correlation (r = 0.70) between burnout and fatigue. Particular attention should be paid to staff who became ill and need to be treated.