ObjectivesBody mass index (BMI) can affect an individual’s health. The night shift is a characteristic of the nursing profession, which is associated with an abnormal BMI. However, few studies have investigated the association between BMI and burnout in Chinese nurses. This study examined the association between BMI and burnout among Chinese nurses.MethodsA total of 1863 nurses from 12 tertiary hospitals in Shandong Province of China were selected. BMI was calculated as body weight divided by height squared. The Maslach Burnout Service Inventory General Survey (MBI-GS) was used to measure the level of burnout among nurses. Ordinal logistic regression was used to analyse the association between BMI and burnout.ResultsIn this study, the prevalence of normal BMI, underweight, overweight, and obesity was 69.2%, 7.5%, 18.2%, and 5.2%, respectively. The prevalence of high emotional exhaustion, high cynicism, and low personal accomplishment among nurses was 26.1%, 38.7%, and 35.6%, respectively. Nurses who were obese were more likely to have high levels of emotional exhaustion (OR=1.493, 95% CI: 1.011 to 2.206) and cynicism (OR=1.511, 95% CI: 1.014 to 2.253), and nurses who were underweight were more likely to have high levels of cynicism (OR=1.593, 95% CI: 1.137 to 2.232) compared with those who were normal weight.ConclusionsObesity was positively associated with emotional exhaustion and cynicism, and being underweight was only positively associated with cynicism among Chinese nurses. Hospital administrators should consider BMI when taking effective measures to reduce burnout among nurses.