OBJECTIVE To estimate the reliability and the validity of the single item burnout measure in a sample of nurses in Greece. METHOD We conducted an online cross-sectional study in Greece with 963 nurses. Data were collected during October 2022. We measured demographic and work-related variables of nurses, i.e. gender, age, chronic disease, self-rated health status, years of experience, and working in COVID-19 ward/intensive care unit. We used the single item burnout (SIB) and the Copenhagen Burnout Inventory (CBI) to measure occupational burnout. Moreover, we used the COVID-19 burnout scale (COVID-19-BS) to measure nurses burnout during the pandemic, and the Patient Health Questionnaire-4 (PHQ-4) to measure anxiety and depression among nurses. RESULTS Intraclass correlation coefficient between the two measurements of the SIB during the test-retest study was 0.986 indicating excellent reliability of the SIB. We found a high correlation between CBI factors and SIB (p<0.001), a moderate correlation between PHQ-4 and SIB (p<0.001), and a low to moderate correlation between COVID-19-BS and SIB (p<0.001). Therefore, concurrent validity of SIB was excellent. Moreover, SIB had high discriminant validity. In particular, nurses with a chronic disease, those with a very poor/poor/moderate health status, and those working in COVID-19 ward/intensive care unit had higher levels of burnout according to the SIB (p<0.001 in all cases). Moreover, we found a positive relationship between years of experience and SIB score (r=0.13, p<0.001). CONCLUSIONS The single item burnout measure is a brief, reliable, and valid tool that we can use as a screening measure to identify individuals at high risk of burnout.